Information systems are part and parcel of organizations. Yet, organizations often struggle to realize the benefits that motivate their introduction of these systems. To derive benefit from a new information system, it must be integrated into the structures and processes of the organization. That is, the system must be organizationally implemented. This book is about organizational implementation, which requires thorough preparations but also continues long after the system has gone live: (1) During the preparations, the implementation is planned. This phase includes specifying the effects pursued with the system, adapting the system and organization to each other, and obtaining buy-in for the planned change. (2) At go-live, the system is put to operational use and the associated organizational changes take effect. This phase is about insisting on the planned change even though go-live is normally hectic and accompanied by a productivity dip. (3) During continued use after go-live, implementation continues as design in use. This phase is long and improvisational. It includes following up on effects realization, but it is just as much about embracing the opportunities that emerge from using the system. Apart from covering the three phases of organizational implementation, the book inserts implementation in an organizational-change context and discusses barriers to implementation as well as boosters of implementation. The book concludes with an outlook to larger-scale issues beyond the implementation of one system in one organization and with an overview of the competences needed in the implementation team, which runs the organizational implementation.