Examines the impact of software process diversity in one specific area: software reuse, which means that the work products developed elsewhere (in another project, group or company) are used again. To learn how to achieve reuse, we initiated a two-year study in 1997 of roughly two dozen European companies that were establishing reuse programmes in the context of process improvement experiments. We discovered that, despite diversity in business context, technical and managerial traditions and company size, companies can indeed achieve reuse, using diverse processes. From that study, we present four companies (Sodalia, Thomson-CSF, Eliop and Chase Information Technology Services) as case histories, selected for the variety and effectiveness of their approaches. These four European companies successfully achieved software reuse despite pursuing radically different processes and technologies. The authors explore the reasons behind the companies' success and present guidelines for others wanting to establish reuse programmes.