Writing in the Bulletin of the American Mathematical Society, William Thurston said: "Mathematicians have developed habits of communication that are often dysfunctional." Our paper describes how the new course Calculus & Mathematica sets up a new method of communication of mathematics in the form of interactive texts running on computers. The lecture hall is replaced by the computer lab. The lecturer is replaced by students actively learning for themselves. Classroom meetings are genuine discussions with the whole class participating. Students do mathematics in much the same way that active research mathematicians do mathematics.