In the era of ubiquitous computing and networking, millions of electronic devices with computing facilities in the public space are connected with each other in ad hoc ways, but are required to behave coherently. Massively multi-agent systems, MMAS can be a major design paradigm or an implementation method for ubiquitous computing and ambient intelligence. As the infrastructure of massively multi-agent systems, technologies such as grid computing together with semantic annotation can be combined with agent technology. A new system design approach, society-centered design, may be realized by embedding participatory technologies in human society.This book originates from the First International Workshop on Massively Multi-Agent Systems, MMAS 2004, held in Kyoto, Japan in December 2004. The 25 revised full selected and invited papers give an excellent introduction and overview on massively multi-agent systems. The papers are organized in parts on massively multi-agent technology, teams and organization, ubiquitous computing and ambient intelligence, and massively multi-agent systems in the public space.