A model for software configuration management that subsumes several existing systems is described. It is patterned after compiler models in which programs are transformed by multiple phases ending in an executable program. We model configuration management as transforming a high-level specification of a software product to be produced into a complete specification capable of being executed to construct the product. This transformational approach is used to model four existing systems and to compare and contrast their operation. © 1989, ACM. All rights reserved.