In order to compete in manufacturing, industry realizes it must work more efficiently with its resources. Three manufacturing techniques have been developed to assist industry in this challenge --MRP, JIT, and OPT. This paper compares these three techniques. It concentrates on the factors that affect production after vendor materials are in-house. A brief discussion of some of the implementation difficulties a company may face during the transition to a new philosophy is also addressed. Finally, a case study of a low volume, highly technical military project is evaluated and analyzed