Part I: Conventional methods for software maintenance and evolution -- Static program analysis methods -- Reverse engineering methods -- Model-based design for ease of maintenance -- Evolution of versions and configuration management -- Part II: Reuse-based software maintenance and evolution -- Mixed-strategy approach: an overview -- Step-by-step introduction to XVCL -- Software similarities: symptoms and causes -- Mixed-strategy approach to generic designe -- Evolution with mixed-strategy approach -- Scaling up the mixed-strategy approach -- Mixed-strategy approach in other projects -- Other techniques related to XVCL -- Evaluation of the mixed-strategy approach.