This chapter introduces an assembly-based method engineering approach for constructing situational analysis and design methods. The approach is supported by a meta-modeling technique, based on UML activity and class diagrams. Both the method engineering approach and meta-modeling technique will be explained and illustrated by case studies. The first case study describes the use of the meta-modeling technique in the analysis of method evolution. The next case study describes the use of situational method engineering, supported by the proposed meta-modeling technique, in method construction. With this research, the authors hope to provide researchers in the information system development domain with a useful approach for analyzing, constructing, and adapting methods.