Book excerpt: Planning and improving of production systems and manufacturing processes is a most complex task in engineering. In small and medium sized enterprises (SME's) it is usually carried out by a group of enterprise planners from different departments within a planning project. The main issue of this research is to overcome the logical and technical boundaries between the highly-interrelated modelling experts and their specific modelling tools and partial planning models as well as to efficiently coordinate their distributed, cooperative planning tasks. Therefore, a methodical integration concept as well as a groupware-based cooperation concept was developed. Now it is possible to combine the large number of sophisticated modelling tools, factory simulators as well as GPM tools, and to guarantee a seamless planning process. The conceptual ideas were implemented in a prototypical toolbox to show the technical realization of the flexible concepts for integration and cooperation support. (Back cover).