<s>
The	O
International	B-Library
Standard	I-Library
Book	I-Library
Number	I-Library
(	O
ISBN	B-Library
)	O
is	O
a	O
numeric	O
commercial	O
book	O
identifier	O
that	O
is	O
intended	O
to	O
be	O
unique	O
.	O
</s>
<s>
Publishers	O
purchase	O
or	O
receive	O
ISBNs	B-Library
from	O
an	O
affiliate	O
of	O
the	O
International	B-Library
ISBN	I-Library
Agency	I-Library
.	O
</s>
<s>
An	O
ISBN	B-Library
is	O
assigned	O
to	O
each	O
separate	O
edition	O
and	O
variation	O
(	O
except	O
reprintings	O
)	O
of	O
a	O
publication	O
.	O
</s>
<s>
For	O
example	O
,	O
an	O
e-book	O
,	O
a	O
paperback	O
and	O
a	O
hardcover	O
edition	O
of	O
the	O
same	O
book	O
will	O
each	O
have	O
a	O
different	O
ISBN	B-Library
.	O
</s>
<s>
The	O
ISBN	B-Library
is	O
ten	O
digits	O
long	O
if	O
assigned	O
before	O
2007	O
,	O
and	O
thirteen	O
digits	O
long	O
if	O
assigned	O
on	O
or	O
after	O
1January	O
2007	O
.	O
</s>
<s>
The	O
method	O
of	O
assigning	O
an	O
ISBN	B-Library
is	O
nation-specific	O
and	O
varies	O
between	O
countries	O
,	O
often	O
depending	O
on	O
how	O
large	O
the	O
publishing	O
industry	O
is	O
within	O
a	O
country	O
.	O
</s>
<s>
The	O
initial	O
ISBN	B-Library
identification	O
format	O
was	O
devised	O
in	O
1967	O
,	O
based	O
upon	O
the	O
9-digit	O
Standard	O
Book	O
Numbering	O
(	O
SBN	O
)	O
created	O
in	O
1966	O
.	O
</s>
<s>
The	O
10-digit	B-Library
ISBN	I-Library
format	O
was	O
developed	O
by	O
the	O
International	O
Organization	O
for	O
Standardization	O
(	O
ISO	O
)	O
and	O
was	O
published	O
in	O
1970	O
as	O
international	O
standard	O
ISO	B-Library
2108	I-Library
(	O
the	O
9-digit	O
SBN	O
code	O
can	O
be	O
converted	O
to	O
a	O
10-digit	B-Library
ISBN	I-Library
by	O
prefixing	O
it	O
with	O
a	O
zero	O
)	O
.	O
</s>
<s>
Privately	O
published	O
books	O
sometimes	O
appear	O
without	O
an	O
ISBN	B-Library
.	O
</s>
<s>
The	O
International	B-Library
ISBN	I-Library
Agency	I-Library
sometimes	O
assigns	O
such	O
books	O
ISBNs	B-Library
on	O
its	O
own	O
initiative	O
.	O
</s>
<s>
The	O
ISBN	B-Library
identification	O
format	O
was	O
conceived	O
in	O
1967	O
in	O
the	O
United	O
Kingdom	O
by	O
David	O
Whitaker	O
(	O
regarded	O
as	O
the	O
"	O
Father	O
of	O
the	O
ISBN	B-Library
"	O
)	O
and	O
in	O
1968	O
in	O
the	O
United	O
States	O
by	O
Emery	O
Koltay	O
(	O
who	O
later	O
became	O
director	O
of	O
the	O
U.S.	O
ISBN	B-Library
agency	O
R	B-Library
.	I-Library
R	I-Library
.	I-Library
Bowker	I-Library
)	O
.	O
</s>
<s>
The	O
10-digit	B-Library
ISBN	I-Library
format	O
was	O
developed	O
by	O
the	O
ISO	O
and	O
was	O
published	O
in	O
1970	O
as	O
international	O
standard	O
ISO	B-Library
2108	I-Library
.	O
</s>
<s>
ISO	O
has	O
appointed	O
the	O
International	B-Library
ISBN	I-Library
Agency	I-Library
as	O
the	O
registration	O
authority	O
for	O
ISBN	B-Library
worldwide	O
and	O
the	O
ISBN	B-Library
Standard	O
is	O
developed	O
under	O
the	O
control	O
of	O
ISO	O
Technical	O
Committee	O
46/Subcommittee	O
9	O
TC	O
46/SC	O
9	O
.	O
</s>
<s>
An	O
SBN	O
may	O
be	O
converted	O
to	O
an	O
ISBN	B-Library
by	O
prefixing	O
the	O
digit	O
"	O
0	O
"	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
second	O
edition	O
of	O
Mr.	O
J	O
.	O
G	O
.	O
Reeder	O
Returns	O
,	O
published	O
by	O
Hodder	O
in	O
1965	O
,	O
has	O
,	O
where	O
"	O
340	O
"	O
indicates	O
the	O
publisher	O
,	O
"	O
01381	O
"	O
is	O
the	O
serial	O
number	O
assigned	O
by	O
the	O
publisher	O
,	O
and	O
"	O
8	O
"	O
is	O
the	O
check	B-Error_Name
digit	I-Error_Name
.	O
</s>
<s>
By	O
prefixing	O
a	O
zero	O
,	O
this	O
can	O
be	O
converted	O
to	O
;	O
the	O
check	B-Error_Name
digit	I-Error_Name
does	O
not	O
need	O
to	O
be	O
re-calculated	O
.	O
</s>
<s>
Since	O
1	O
January	O
2007	O
,	O
ISBNs	B-Library
have	O
contained	O
thirteen	O
digits	O
,	O
a	O
format	O
that	O
is	O
compatible	O
with	O
"	O
Bookland	O
"	O
European	O
Article	O
Numbers	O
,	O
which	O
have	O
13	O
digits	O
.	O
</s>
<s>
A	O
separate	O
ISBN	B-Library
is	O
assigned	O
to	O
each	O
edition	O
and	O
variation	O
(	O
except	O
reprintings	O
)	O
of	O
a	O
publication	O
.	O
</s>
<s>
For	O
example	O
,	O
an	O
ebook	O
,	O
audiobook	O
,	O
paperback	O
,	O
and	O
hardcover	O
edition	O
of	O
the	O
same	O
book	O
will	O
each	O
have	O
a	O
different	O
ISBN	B-Library
assigned	O
to	O
it	O
.	O
</s>
<s>
The	O
ISBN	B-Library
is	O
thirteen	O
digits	O
long	O
if	O
assigned	O
on	O
or	O
after	O
1	O
January	O
2007	O
,	O
and	O
ten	O
digits	O
long	O
if	O
assigned	O
before	O
2007	O
.	O
</s>
<s>
An	O
International	B-Library
Standard	I-Library
Book	I-Library
Number	I-Library
consists	O
of	O
four	O
parts	O
(	O
if	O
it	O
is	O
a	O
10-digit	B-Library
ISBN	I-Library
)	O
or	O
five	O
parts	O
(	O
for	O
a	O
13-digit	B-Library
ISBN	I-Library
)	O
.	O
</s>
<s>
Section	O
5	O
of	O
the	O
International	B-Library
ISBN	I-Library
Agency	I-Library
's	O
official	O
user	O
manual	O
describes	O
the	O
structure	O
of	O
the	O
13-digit	B-Library
ISBN	I-Library
,	O
as	O
follows	O
:	O
</s>
<s>
for	O
a	O
13-digit	B-Library
ISBN	I-Library
,	O
a	O
prefix	O
element	O
–	O
a	O
GS1	O
prefix	O
:	O
so	O
far	O
978	O
or	O
979	O
have	O
been	O
made	O
available	O
by	O
GS1	O
,	O
</s>
<s>
a	O
checksum	B-Algorithm
character	O
or	O
check	B-Error_Name
digit	I-Error_Name
.	O
</s>
<s>
A	O
13-digit	B-Library
ISBN	I-Library
can	O
be	O
separated	O
into	O
its	O
parts	O
(	O
prefix	O
element	O
,	O
registration	O
group	O
,	O
registrant	O
,	O
publication	O
and	O
check	B-Error_Name
digit	I-Error_Name
)	O
,	O
and	O
when	O
this	O
is	O
done	O
it	O
is	O
customary	O
to	O
separate	O
the	O
parts	O
with	O
hyphens	O
or	O
spaces	O
.	O
</s>
<s>
Separating	O
the	O
parts	O
(	O
registration	O
group	O
,	O
registrant	O
,	O
publication	O
and	O
check	B-Error_Name
digit	I-Error_Name
)	O
of	O
a	O
10-digit	B-Library
ISBN	I-Library
is	O
also	O
done	O
with	O
either	O
hyphens	O
or	O
spaces	O
.	O
</s>
<s>
Figuring	O
out	O
how	O
to	O
correctly	O
separate	O
a	O
given	O
ISBN	B-Library
is	O
complicated	O
,	O
because	O
most	O
of	O
the	O
parts	O
do	O
not	O
use	O
a	O
fixed	O
number	O
of	O
digits	O
.	O
</s>
<s>
ISBN	B-Library
issuance	O
is	O
country-specific	O
,	O
in	O
that	O
ISBNs	B-Library
are	O
issued	O
by	O
the	O
ISBN	B-Library
registration	O
agency	O
that	O
is	O
responsible	O
for	O
that	O
country	O
or	O
territory	O
regardless	O
of	O
the	O
publication	O
language	O
.	O
</s>
<s>
The	O
ranges	O
of	O
ISBNs	B-Library
assigned	O
to	O
any	O
particular	O
country	O
are	O
based	O
on	O
the	O
publishing	O
profile	O
of	O
the	O
country	O
concerned	O
,	O
and	O
so	O
the	O
ranges	O
will	O
vary	O
depending	O
on	O
the	O
number	O
of	O
books	O
and	O
the	O
number	O
,	O
type	O
,	O
and	O
size	O
of	O
publishers	O
that	O
are	O
active	O
.	O
</s>
<s>
Some	O
ISBN	B-Library
registration	O
agencies	O
are	O
based	O
in	O
national	O
libraries	O
or	O
within	O
ministries	O
of	O
culture	O
and	O
thus	O
may	O
receive	O
direct	O
funding	O
from	O
the	O
government	O
to	O
support	O
their	O
services	O
.	O
</s>
<s>
In	O
other	O
cases	O
,	O
the	O
ISBN	B-Library
registration	O
service	O
is	O
provided	O
by	O
organisations	O
such	O
as	O
bibliographic	O
data	O
providers	O
that	O
are	O
not	O
government	O
funded	O
.	O
</s>
<s>
A	O
full	O
directory	O
of	O
ISBN	B-Library
agencies	O
is	O
available	O
on	O
the	O
International	B-Library
ISBN	I-Library
Agency	I-Library
.	O
</s>
<s>
The	O
ISBN	B-Library
registration	O
group	O
element	O
is	O
a	O
1-to-5-digit	O
number	O
that	O
is	O
valid	O
within	O
a	O
single	O
prefix	O
element	O
(	O
i.e.	O
</s>
<s>
Within	O
the	O
979	O
prefix	O
element	O
,	O
the	O
registration	O
group	O
0	O
is	O
reserved	O
for	O
compatibility	O
with	O
International	O
Standard	O
Music	O
Numbers	O
(	O
ISMNs	O
)	O
,	O
but	O
such	O
material	O
is	O
not	O
actually	O
assigned	O
an	O
ISBN	B-Library
.	O
</s>
<s>
The	O
original	O
9-digit	O
standard	O
book	O
number	O
(	O
SBN	O
)	O
had	O
no	O
registration	O
group	O
identifier	O
,	O
but	O
prefixing	O
a	O
zero	O
to	O
a	O
9-digit	O
SBN	O
creates	O
a	O
valid	O
10-digit	B-Library
ISBN	I-Library
.	O
</s>
<s>
The	O
national	O
ISBN	B-Library
agency	O
assigns	O
the	O
registrant	O
element	O
(	O
cf	O
.	O
</s>
<s>
:Category:ISBN	O
agencies	O
)	O
and	O
an	O
accompanying	O
series	O
of	O
ISBNs	B-Library
within	O
that	O
registrant	O
element	O
to	O
the	O
publisher	O
;	O
the	O
publisher	O
then	O
allocates	O
one	O
of	O
the	O
ISBNs	B-Library
to	O
each	O
of	O
its	O
books	O
.	O
</s>
<s>
In	O
most	O
countries	O
,	O
a	O
book	O
publisher	O
is	O
not	O
legally	O
required	O
to	O
assign	O
an	O
ISBN	B-Library
,	O
although	O
most	O
large	O
bookstores	O
only	O
handle	O
publications	O
that	O
have	O
ISBNs	B-Library
assigned	O
to	O
them	O
.	O
</s>
<s>
The	O
International	B-Library
ISBN	I-Library
Agency	I-Library
maintains	O
the	O
details	O
of	O
over	O
one	O
million	O
ISBN	B-Library
prefixes	O
and	O
publishers	O
in	O
the	O
.	O
</s>
<s>
Publishers	O
receive	O
blocks	O
of	O
ISBNs	B-Library
,	O
with	O
larger	O
blocks	O
allotted	O
to	O
publishers	O
expecting	O
to	O
need	O
them	O
;	O
a	O
small	O
publisher	O
may	O
receive	O
ISBNs	B-Library
of	O
one	O
or	O
more	O
digits	O
for	O
the	O
registration	O
group	O
identifier	O
,	O
several	O
digits	O
for	O
the	O
registrant	O
,	O
and	O
a	O
single	O
digit	O
for	O
the	O
publication	O
element	O
.	O
</s>
<s>
Once	O
that	O
block	O
of	O
ISBNs	B-Library
is	O
used	O
,	O
the	O
publisher	O
may	O
receive	O
another	O
block	O
of	O
ISBNs	B-Library
,	O
with	O
a	O
different	O
registrant	O
element	O
.	O
</s>
<s>
By	O
using	O
variable	O
block	O
lengths	O
,	O
registration	O
agencies	O
are	O
able	O
to	O
customise	O
the	O
allocations	O
of	O
ISBNs	B-Library
that	O
they	O
make	O
to	O
publishers	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
large	O
publisher	O
may	O
be	O
given	O
a	O
block	O
of	O
ISBNs	B-Library
where	O
fewer	O
digits	O
are	O
allocated	O
for	O
the	O
registrant	O
element	O
and	O
many	O
digits	O
are	O
allocated	O
for	O
the	O
publication	O
element	O
;	O
likewise	O
,	O
countries	O
publishing	O
many	O
titles	O
have	O
few	O
allocated	O
digits	O
for	O
the	O
registration	O
group	O
identifier	O
and	O
many	O
for	O
the	O
registrant	O
and	O
publication	O
elements	O
.	O
</s>
<s>
Here	O
are	O
some	O
sample	O
ISBN	B-Library
codes	O
,	O
illustrating	O
block	O
length	O
variations	O
.	O
</s>
<s>
ISBN	B-Library
Country	O
or	O
area	O
Publisher	O
99921-58-10-7	O
Qatar	O
NCCAH	O
,	O
Doha	O
9971-5-0210-0	O
Singapore	O
World	O
Scientific	O
960-425-059-0	O
Greece	O
Sigma	O
Publications	O
80-902734-1-6	O
Czech	O
Republic	O
;	O
Slovakia	O
Taita	O
Publishers	O
85-359-0277-5	O
Brazil	O
Companhia	O
das	O
Letras	O
1-84356-028-3	O
English-speaking	O
area	O
Simon	O
Wallenberg	O
Press	O
0-684-84328-5	O
English-speaking	O
area	O
Scribner	O
0-8044-2957-X	O
English-speaking	O
area	O
Frederick	O
Ungar	O
0-85131-041-9	O
English-speaking	O
area	O
J	O
.	O
</s>
<s>
A	O
check	B-Error_Name
digit	I-Error_Name
is	O
a	O
form	O
of	O
redundancy	O
check	O
used	O
for	O
error	B-Error_Name
detection	I-Error_Name
,	O
the	O
decimal	O
equivalent	O
of	O
a	O
binary	O
check	B-Error_Name
bit	I-Error_Name
.	O
</s>
<s>
The	O
method	O
for	O
the	O
10-digit	B-Library
ISBN	I-Library
is	O
an	O
extension	O
of	O
that	O
for	O
SBNs	O
,	O
so	O
the	O
two	O
systems	O
are	O
compatible	O
;	O
an	O
SBN	O
prefixed	O
with	O
a	O
zero	O
(	O
the	O
10-digit	B-Library
ISBN	I-Library
)	O
will	O
give	O
the	O
same	O
check	B-Error_Name
digit	I-Error_Name
as	O
the	O
SBN	O
without	O
the	O
zero	O
.	O
</s>
<s>
The	O
check	B-Error_Name
digit	I-Error_Name
is	O
base	O
eleven	O
,	O
and	O
can	O
be	O
an	O
integer	O
between	O
0	O
and	O
9	O
,	O
or	O
an	O
'	O
X	O
 '	O
.	O
</s>
<s>
The	O
system	O
for	O
13-digit	B-Library
ISBNs	I-Library
is	O
not	O
compatible	O
with	O
SBNs	O
and	O
will	O
,	O
in	O
general	O
,	O
give	O
a	O
different	O
check	B-Error_Name
digit	I-Error_Name
from	O
the	O
corresponding	O
10-digit	B-Library
ISBN	I-Library
,	O
so	O
does	O
not	O
provide	O
the	O
same	O
protection	O
against	O
transposition	O
.	O
</s>
<s>
According	O
to	O
the	O
2001	O
edition	O
of	O
the	O
International	B-Library
ISBN	I-Library
Agency	I-Library
's	O
official	O
user	O
manual	O
,	O
the	O
ISBN	B-Library
check	B-Error_Name
digit	I-Error_Name
(	O
which	O
is	O
the	O
last	O
digit	O
of	O
the	O
10-digit	B-Library
ISBN	I-Library
)	O
must	O
range	O
from	O
0	O
to	O
10	O
(	O
the	O
symbol	O
'	O
X	O
 '	O
is	O
used	O
for	O
10	O
)	O
,	O
and	O
must	O
be	O
such	O
that	O
the	O
sum	O
of	O
the	O
ten	O
digits	O
,	O
each	O
multiplied	O
by	O
its	O
(	O
integer	O
)	O
weight	O
,	O
descending	O
from	O
10	O
to	O
1	O
,	O
is	O
a	O
multiple	O
of	O
11	O
.	O
</s>
<s>
For	O
example	O
,	O
for	O
an	O
ISBN	B-Library
of	O
0-306-40615-2	O
:	O
</s>
<s>
It	O
is	O
also	O
true	O
for	O
ISBNs	B-Library
that	O
the	O
sum	O
of	O
all	O
ten	O
digits	O
,	O
each	O
multiplied	O
by	O
its	O
weight	O
in	O
ascending	O
order	O
from	O
1	O
to	O
10	O
,	O
is	O
a	O
multiple	O
of	O
11	O
.	O
</s>
<s>
The	O
two	O
most	O
common	O
errors	O
in	O
handling	O
an	O
ISBN	B-Library
(	O
e.g.	O
</s>
<s>
It	O
can	O
be	O
proven	O
mathematically	O
that	O
all	O
pairs	O
of	O
valid	O
ISBNs	B-Library
differ	O
in	O
at	O
least	O
two	O
digits	O
.	O
</s>
<s>
It	O
can	O
also	O
be	O
proven	O
that	O
there	O
are	O
no	O
pairs	O
of	O
valid	O
ISBNs	B-Library
with	O
eight	O
identical	O
digits	O
and	O
two	O
transposed	O
digits	O
.	O
</s>
<s>
(	O
These	O
proofs	O
are	O
true	O
because	O
the	O
ISBN	B-Library
is	O
less	O
than	O
eleven	O
digits	O
long	O
and	O
because	O
11	O
is	O
a	O
prime	O
number	O
.	O
)	O
</s>
<s>
The	O
ISBN	B-Library
check	B-Error_Name
digit	I-Error_Name
method	O
therefore	O
ensures	O
that	O
it	O
will	O
always	O
be	O
possible	O
to	O
detect	O
these	O
two	O
most	O
common	O
types	O
of	O
error	O
,	O
i.e.	O
,	O
if	O
either	O
of	O
these	O
types	O
of	O
error	O
has	O
occurred	O
,	O
the	O
result	O
will	O
never	O
be	O
a	O
valid	O
ISBN	B-Library
–	O
the	O
sum	O
of	O
the	O
digits	O
multiplied	O
by	O
their	O
weights	O
will	O
never	O
be	O
a	O
multiple	O
of	O
11	O
.	O
</s>
<s>
However	O
,	O
if	O
the	O
error	O
were	O
to	O
occur	O
in	O
the	O
publishing	O
house	O
and	O
remain	O
undetected	O
,	O
the	O
book	O
would	O
be	O
issued	O
with	O
an	O
invalid	O
ISBN	B-Library
.	O
</s>
<s>
In	O
contrast	O
,	O
it	O
is	O
possible	O
for	O
other	O
types	O
of	O
error	O
,	O
such	O
as	O
two	O
altered	O
non-transposed	O
digits	O
,	O
or	O
three	O
altered	O
digits	O
,	O
to	O
result	O
in	O
a	O
valid	O
ISBN	B-Library
(	O
although	O
it	O
is	O
still	O
unlikely	O
)	O
.	O
</s>
<s>
Each	O
of	O
the	O
first	O
nine	O
digits	O
of	O
the	O
10-digit	B-Library
ISBN	I-Library
–	O
excluding	O
the	O
check	B-Error_Name
digit	I-Error_Name
itself	O
–	O
is	O
multiplied	O
by	O
its	O
(	O
integer	O
)	O
weight	O
,	O
descending	O
from	O
10	O
to	O
2	O
,	O
and	O
the	O
sum	O
of	O
these	O
nine	O
products	O
found	O
.	O
</s>
<s>
The	O
value	O
of	O
the	O
check	B-Error_Name
digit	I-Error_Name
is	O
simply	O
the	O
one	O
number	O
between	O
0	O
and	O
10	O
which	O
,	O
when	O
added	O
to	O
this	O
sum	O
,	O
means	O
the	O
total	O
is	O
a	O
multiple	O
of	O
11	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
check	B-Error_Name
digit	I-Error_Name
for	O
an	O
ISBN	B-Library
of	O
0-306-40615-	O
?	O
</s>
<s>
Therefore	O
,	O
the	O
check	B-Error_Name
digit	I-Error_Name
has	O
to	O
be	O
2	O
,	O
and	O
the	O
complete	O
sequence	O
is	O
ISBN	B-Library
0-306-40615-2	O
.	O
</s>
<s>
Alternatively	O
,	O
modular	O
arithmetic	O
is	O
convenient	O
for	O
calculating	O
the	O
check	B-Error_Name
digit	I-Error_Name
using	O
modulus	O
11	O
.	O
</s>
<s>
This	O
remainder	O
plus	O
the	O
check	B-Error_Name
digit	I-Error_Name
must	O
equal	O
either	O
0	O
or	O
11	O
.	O
</s>
<s>
Therefore	O
,	O
the	O
check	B-Error_Name
digit	I-Error_Name
is	O
(	O
11	O
minus	O
the	O
remainder	O
of	O
the	O
sum	O
of	O
the	O
products	O
modulo	O
11	O
)	O
modulo	O
11	O
.	O
</s>
<s>
Without	O
the	O
second	O
modulo	O
operation	O
,	O
the	O
calculation	O
could	O
result	O
in	O
a	O
check	B-Error_Name
digit	I-Error_Name
value	O
of	O
,	O
which	O
is	O
invalid	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
check	B-Error_Name
digit	I-Error_Name
for	O
the	O
ISBN	B-Library
of	O
0-306-40615-	O
?	O
</s>
<s>
Thus	O
the	O
check	B-Error_Name
digit	I-Error_Name
is	O
2	O
.	O
</s>
<s>
The	O
modular	O
reduction	O
can	O
be	O
done	O
once	O
at	O
the	O
end	O
,	O
as	O
shown	O
above	O
(	O
in	O
which	O
case	O
s	O
could	O
hold	O
a	O
value	O
as	O
large	O
as	O
496	O
,	O
for	O
the	O
invalid	O
ISBN	B-Library
99999-999-9-X	O
)	O
,	O
or	O
s	O
and	O
t	O
could	O
be	O
reduced	O
by	O
a	O
conditional	O
subtract	O
after	O
each	O
addition	O
.	O
</s>
<s>
Appendix	O
1	O
of	O
the	O
International	B-Library
ISBN	I-Library
Agency	I-Library
's	O
official	O
user	O
manual	O
describes	O
how	O
the	O
13-digit	B-Library
ISBN	I-Library
check	B-Error_Name
digit	I-Error_Name
is	O
calculated	O
.	O
</s>
<s>
The	O
ISBN	B-Library
check	B-Error_Name
digit	I-Error_Name
,	O
which	O
is	O
the	O
last	O
digit	O
of	O
the	O
ISBN	B-Library
,	O
must	O
range	O
from	O
0	O
to	O
9	O
and	O
must	O
be	O
such	O
that	O
the	O
sum	O
of	O
all	O
the	O
thirteen	O
digits	O
,	O
each	O
multiplied	O
by	O
its	O
(	O
integer	O
)	O
weight	O
,	O
alternating	O
between	O
1	O
and	O
3	O
,	O
is	O
a	O
multiple	O
of	O
10	O
.	O
</s>
<s>
As	O
ISBN	B-Library
is	O
a	O
subset	O
of	O
EAN-13	O
,	O
the	O
algorithm	O
for	O
calculating	O
the	O
check	B-Error_Name
digit	I-Error_Name
is	O
exactly	O
the	O
same	O
for	O
both	O
.	O
</s>
<s>
The	O
calculation	O
of	O
an	O
ISBN	B-Library
check	B-Error_Name
digit	I-Error_Name
begins	O
with	O
the	O
first	O
twelve	O
digits	O
of	O
the	O
13-digit	B-Library
ISBN	I-Library
(	O
thus	O
excluding	O
the	O
check	B-Error_Name
digit	I-Error_Name
itself	O
)	O
.	O
</s>
<s>
A	O
zero	O
replaces	O
a	O
ten	O
,	O
so	O
,	O
in	O
all	O
cases	O
,	O
a	O
single	O
check	B-Error_Name
digit	I-Error_Name
results	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
ISBN	B-Library
check	B-Error_Name
digit	I-Error_Name
of	O
978-0-306-40615-	O
?	O
</s>
<s>
Thus	O
,	O
the	O
check	B-Error_Name
digit	I-Error_Name
is	O
7	O
,	O
and	O
the	O
complete	O
sequence	O
is	O
ISBN	B-Library
978-0-306-40615-7	O
.	O
</s>
<s>
In	O
general	O
,	O
the	O
ISBN	B-Library
check	B-Error_Name
digit	I-Error_Name
is	O
calculated	O
as	O
follows	O
.	O
</s>
<s>
This	O
check	O
system	O
–	O
similar	O
to	O
the	O
UPC	O
check	B-Error_Name
digit	I-Error_Name
formula	O
–	O
does	O
not	O
catch	O
all	O
errors	O
of	O
adjacent	O
digit	O
transposition	O
.	O
</s>
<s>
Specifically	O
,	O
if	O
the	O
difference	O
between	O
two	O
adjacent	O
digits	O
is	O
5	O
,	O
the	O
check	B-Error_Name
digit	I-Error_Name
will	O
not	O
catch	O
their	O
transposition	O
.	O
</s>
<s>
However	O
,	O
19	O
and	O
9	O
are	O
congruent	O
modulo	O
10	O
,	O
and	O
so	O
produce	O
the	O
same	O
,	O
final	O
result	O
:	O
both	O
ISBNs	B-Library
will	O
have	O
a	O
check	B-Error_Name
digit	I-Error_Name
of	O
7	O
.	O
</s>
<s>
The	O
ISBN	B-Library
formula	O
uses	O
the	O
prime	O
modulus	O
11	O
which	O
avoids	O
this	O
blind	O
spot	O
,	O
but	O
requires	O
more	O
than	O
the	O
digits	O
0	O
–	O
9	O
to	O
express	O
the	O
check	B-Error_Name
digit	I-Error_Name
.	O
</s>
<s>
An	O
ISBN	B-Library
is	O
converted	O
to	O
ISBN	B-Library
by	O
prepending	O
"	O
978	O
"	O
to	O
the	O
ISBN	B-Library
and	O
recalculating	O
the	O
final	O
checksum	B-Error_Name
digit	I-Error_Name
using	O
the	O
ISBN	B-Library
algorithm	O
.	O
</s>
<s>
Publishers	O
and	O
libraries	O
have	O
varied	O
policies	O
about	O
the	O
use	O
of	O
the	O
ISBN	B-Library
check	B-Error_Name
digit	I-Error_Name
.	O
</s>
<s>
Publishers	O
sometimes	O
fail	O
to	O
check	O
the	O
correspondence	O
of	O
a	O
book	O
title	O
and	O
its	O
ISBN	B-Library
before	O
publishing	O
it	O
;	O
that	O
failure	O
causes	O
book	O
identification	O
problems	O
for	O
libraries	O
,	O
booksellers	O
,	O
and	O
readers	O
.	O
</s>
<s>
Most	O
libraries	O
and	O
booksellers	O
display	O
the	O
book	O
record	O
for	O
an	O
invalid	O
ISBN	B-Library
issued	O
by	O
the	O
publisher	O
.	O
</s>
<s>
The	O
Library	O
of	O
Congress	O
catalogue	O
contains	O
books	O
published	O
with	O
invalid	O
ISBNs	B-Library
,	O
which	O
it	O
usually	O
tags	O
with	O
the	O
phrase	O
"	O
Cancelled	O
ISBN	B-Library
"	O
.	O
</s>
<s>
However	O
,	O
book-ordering	O
systems	O
will	O
not	O
search	O
for	O
a	O
book	O
if	O
an	O
invalid	O
ISBN	B-Library
is	O
entered	O
to	O
its	O
search	O
engine	O
.	O
</s>
<s>
The	O
International	O
Union	O
Library	O
Catalog	O
(	O
a.k.a.	O
,	O
WorldCat	B-Library
OCLC	O
–	O
Online	O
Computer	O
Library	O
Center	O
system	O
)	O
often	O
indexes	O
by	O
invalid	O
ISBNs	B-Library
,	O
if	O
the	O
book	O
is	O
indexed	O
in	O
that	O
way	O
by	O
a	O
member	O
library	O
.	O
</s>
<s>
Only	O
the	O
term	O
"	O
ISBN	B-Library
"	O
should	O
be	O
used	O
;	O
the	O
terms	O
"	O
eISBN	O
"	O
and	O
"	O
e-ISBN	O
"	O
have	O
historically	O
been	O
sources	O
of	O
confusion	O
and	O
should	O
be	O
avoided	O
.	O
</s>
<s>
If	O
a	O
book	O
exists	O
in	O
one	O
or	O
more	O
digital	O
(	O
e-book	O
)	O
formats	O
,	O
each	O
of	O
those	O
formats	O
must	O
have	O
its	O
own	O
ISBN	B-Library
.	O
</s>
<s>
In	O
other	O
words	O
,	O
each	O
of	O
the	O
three	O
separate	O
EPUB	O
,	O
Amazon	B-General_Concept
Kindle	I-General_Concept
,	O
and	O
PDF	B-Application
formats	I-Application
of	O
a	O
particular	O
book	O
will	O
have	O
its	O
own	O
specific	O
ISBN	B-Library
.	O
</s>
<s>
They	O
should	O
not	O
share	O
the	O
ISBN	B-Library
of	O
the	O
paper	O
version	O
,	O
and	O
there	O
is	O
no	O
generic	O
"	O
eISBN	O
"	O
which	O
encompasses	O
all	O
the	O
e-book	O
formats	O
for	O
a	O
title	O
.	O
</s>
<s>
For	O
10-digit	B-Library
ISBNs	I-Library
,	O
the	O
number	O
"	O
978	O
"	O
,	O
the	O
Bookland	O
"	O
country	O
code	O
"	O
,	O
is	O
prefixed	O
to	O
the	O
ISBN	B-Library
in	O
the	O
barcode	O
data	O
,	O
and	O
the	O
check	B-Error_Name
digit	I-Error_Name
is	O
recalculated	O
according	O
to	O
the	O
EAN-13	O
formula	O
(	O
modulo	O
10	O
,	O
1×	O
and	O
3×	O
weighting	O
on	O
alternating	O
digits	O
)	O
.	O
</s>
<s>
Partly	O
because	O
of	O
an	O
expected	O
shortage	O
in	O
certain	O
ISBN	B-Library
categories	O
,	O
the	O
International	O
Organization	O
for	O
Standardization	O
(	O
ISO	O
)	O
decided	O
to	O
migrate	O
to	O
a	O
13-digit	B-Library
ISBN	I-Library
(	O
ISBN	B-Library
)	O
.	O
</s>
<s>
The	O
process	O
began	O
on	O
1	O
January	O
2005	O
and	O
was	O
planned	O
to	O
conclude	O
on	O
1	O
January	O
2007	O
.	O
,	O
all	O
the	O
13-digit	B-Library
ISBNs	I-Library
began	O
with	O
978	O
.	O
</s>
<s>
As	O
the	O
978	O
ISBN	B-Library
supply	O
is	O
exhausted	O
,	O
the	O
979	O
prefix	O
was	O
introduced	O
.	O
</s>
<s>
The	O
10-digit	O
ISMN	O
codes	O
differed	O
visually	O
as	O
they	O
began	O
with	O
an	O
"	O
M	O
"	O
letter	O
;	O
the	O
bar	O
code	O
represents	O
the	O
"	O
M	O
"	O
as	O
a	O
zero	O
,	O
and	O
for	O
checksum	B-Algorithm
purposes	O
it	O
counted	O
as	O
a	O
3	O
.	O
</s>
<s>
All	O
ISMNs	O
are	O
now	O
thirteen	O
digits	O
commencing	O
;	O
to	O
will	O
be	O
used	O
by	O
ISBN	B-Library
.	O
</s>
<s>
Publisher	O
identification	O
code	O
numbers	O
are	O
unlikely	O
to	O
be	O
the	O
same	O
in	O
the	O
978	O
and	O
979	O
ISBNs	B-Library
,	O
likewise	O
,	O
there	O
is	O
no	O
guarantee	O
that	O
language	O
area	O
code	O
numbers	O
will	O
be	O
the	O
same	O
.	O
</s>
<s>
Moreover	O
,	O
the	O
10-digit	B-Library
ISBN	I-Library
check	B-Error_Name
digit	I-Error_Name
generally	O
is	O
not	O
the	O
same	O
as	O
the	O
13-digit	B-Library
ISBN	I-Library
check	B-Error_Name
digit	I-Error_Name
.	O
</s>
<s>
Because	O
the	O
GTIN-13	O
is	O
part	O
of	O
the	O
Global	O
Trade	O
Item	O
Number	O
(	O
GTIN	O
)	O
system	O
(	O
that	O
includes	O
the	O
GTIN-14	O
,	O
the	O
GTIN-12	O
,	O
and	O
the	O
GTIN-8	O
)	O
,	O
the	O
13-digit	B-Library
ISBN	I-Library
falls	O
within	O
the	O
14-digit	O
data	O
field	O
range	O
.	O
</s>
<s>
Barcode	O
format	O
compatibility	O
is	O
maintained	O
,	O
because	O
(	O
aside	O
from	O
the	O
group	O
breaks	O
)	O
the	O
ISBN	B-Library
barcode	O
format	O
is	O
identical	O
to	O
the	O
EAN	O
barcode	O
format	O
of	O
existing	O
10-digit	B-Library
ISBNs	I-Library
.	O
</s>
<s>
So	O
,	O
migration	O
to	O
an	O
EAN-based	O
system	O
allows	O
booksellers	O
the	O
use	O
of	O
a	O
single	O
numbering	O
system	O
for	O
both	O
books	O
and	O
non-book	O
products	O
that	O
is	O
compatible	O
with	O
existing	O
ISBN	B-Library
based	O
data	O
,	O
with	O
only	O
minimal	O
changes	O
to	O
information	B-General_Concept
technology	I-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
The	O
upgrading	O
of	O
the	O
UPC	O
barcode	O
system	O
to	O
full	O
EAN-13	O
,	O
in	O
2005	O
,	O
eased	O
migration	O
to	O
the	O
ISBN	B-Library
in	O
North	O
America	O
.	O
</s>
