Mathematicians at Ithaca College plan to develop a problem-based mainstream calculus curriculum. These complex problems will require a minimum of several weeks to solve. The structure of the problems will vary from "case study" to "open-ended". Groups of students working together will solve problems which develop essential parts of the calculus, and use calculator/computers where relevant. In-depth interviews with twenty-five faculty members from accounting, biology, chemistry, economics, finance, management, politics, psychology, physics will identify realistic problems. Two experimental courses sections of Calculus I will be taught in the Fall of 1989. In the Spring of 1989 a one-day conference on the "Future of Calculus" will be held at Ithaca College. Ithaca College will share 45% of the cost of the project.