BPM systems enable enterprises to optimize their business processes and to gain competitive advantage in the fast evolving global market. The need to involve end users in process composition during the implementation of BPM systems in enterprises is clearly perceived. End users have detailed business domain expertise but limited technical skills. Thus upfront process modeling remains inaccessible for them. This book presents a framework for end-user driven composition of both: (i) weakly-structured process models for supporting ad-hoc, human-centric business processes, and (ii) structured process models for automation of rigidly recurring processes through workflow engines. Process composition is based on collaborative task management. The framework founds on empirical studies, which outline the potentials for involving end users in process composition. The framework provides a task management model, composition methods for ad-hoc and structured processes, and a holistic concept and architecture for process composition. These concepts can be used to facilitate the adoption of BPM in enterprises.