The calculus curriculum is being revised to provide students with more complex, real world problems, to help them develop the skills involved in performing multi-step reasoning, and to help them learn to express mathematical ideas precisely and coherently. A unique computational environment is being developed in which students use the computer as both a tutoring device and a computational aid. The system, called the Calculus Companion, consists of a user-friendly interface to the computer algebra system MAPLE and numerical computation and graphical display routines.