Asimov's famous long story "The Ugly Little Boy" (cf. the equally renowned "Nightfall," novelized by the authors in 1990) first appeared in 1958 in Galaxy magazine and described the emotional repercussions resulting from a 21st-century time-travel experiment in which a Neanderthal child is brought into the present. Like "Nightfall," it struck a sentimental and enduring chord in the science-fiction collective consciousness. The novel version here extends the story in two directions: the motives and interactions of the scientists involved in the experiment are explored in greater detail, while an entire new interwoven thread delineates the Neanderthal culture from which Timmy, the title figure, is plucked. Other than these, the plot remains pretty much the same, with the ending exactly as before: indeed, how could it be otherwise? Readers who preferred the novelized Nightfall will dive right in, as will those curious about the authors' ideas on prehistory and anthropology. Skeptics and cynics, however, will again simply wonder why they bothered.