This book constitutes the refereed proceedings of the 8th International Conference on Software Reuse, ICSR-8, held in Madrid, Spain in July 2004. from numerous submissions. The papers are organized in topical sections on software variability: requirements; testing reusable software; feature modeling; aspect-oriented software development; component and service development; code level reuse; libraries, classification, and retrieval; model-based approaches; transformation and generation; and requirements.