The topic of my sabbatical project consists of reasoning about agreement technologies [3,6,14], where semantics technologies define the set of possible agreements, norms and organizations determine constraints that the agreements have to satisfy, organisational structures define the capabilities of roles, argumentation methods are used to make agents reach agreements, and trust mechanisms are used to build long-term relationships. The challenge of the project is to combine the wide variety of logics for individual and collective reasoning used in agreement technologies, such as judgment aggregation, deontic logic and argumentation theory. Besides using Gabbay’s fibring methodology , I define each individual reasoning method by its input/output behavior, and apply techniques from input/output logic  to study their interaction. I choose Stanford University for this sabbatical for two reasons. First, Prof. Johan van Benthem of Stanford University develops in “Logical dynamics of information and interaction”  a new view of logic as a theory of information-driven agency and intelligent interaction between many agents – with conversation, argumentation and games as guiding examples. I believe this approach is very relevant for agreement technologies. Second, the formalisms we develop and study in my group may be popular in Europe, but they are less known in the USA. I already interact with many researchers in Europe, but have less cooperation with researchers in the USA.A sabbatical offers not only the opportunity to combine insights obtained in the past period, but also to provide the basis for research in the coming period. Therefore, besides writing a book summarizing work on reasoning for agreement technologies I have been engaged in over the past seven years, I will also learn about the latest developments in modal logic and establish new contacts.I will travel with my wife and two children to San Francisco and stay there for six months. The project plan is structured by the book, which I have been planning for over a year. Together with my wife I visited San Francisco in August 2011 to look for schools for the children, and to make inventory of places for my wife to work (she is an artist). Due to the timely preparation, risks are well managed. The requested funding follows the guidelines, there are no special requests.