This paper describes the PECAN family of program development systems. PECAN supports multiple views of the user's program. The views can be representations of the program or of the corresponding semantics. The primary program view is a syntax-directed editor. The current semantic views include expression trees, data type diagrams, flow graphs, and the symbol table. PECAN is designed to make effective use of powerful personal machines with high-resolution graphics displays and is currently implemented on APOLLO workstations.