Process programming is regarded as a critical approach in many cooperative process related areas including software engineering, workflow management, business process management, etc. Many process models, languages, and corresponding runtime support systems have been developed. We argue that a comprehensive library for process programming is essential for the acceptance, popularity, and success of this new programming paradigm. We define an architecture of such a library and present some mechanisms on how the architecture is implemented in the context of P, a process language and system for developing integrated cooperation applications.