Abstract: To help a user program a computer target system to solve problems, the computer system is provided with predefined capabilities and the user is provided with a knowledge system that includes knowledge about applying the capabilities to effectively and efficiently solve the user's problems. The knowledge system provides automatic programming for solving problems within a particular domain, rejects problems that cannot be solved using the available capabilities of the target computer, and explains how and why a certain program was generated or why a program cannot be generated to solve a given problem.