This book constitutes the proceedings of the 12th German Conference on Multiagent System Technologies, MATES 2014, held in Stuttgart, Germany, in September 2014. The 9 full papers and 7 short papers included in this volume were carefully reviewed and selected from 31 submissions. The book also contains 2 invited talks. The papers are organized in topical sections named: mechanisms, negotiation, and game theory; multiagent planning, learning, and control; and multiagent systems engineering, modeling and simulation.

This book constitutes the proceedings of the 13th German Conference on Multiagent System Technologies, MATES 2015, held in Cottbus, Germany, in September 2015.
The 11 full papers papers presented together with 2 short papers, 1 invited paper and 4 extended abstracts of doctoral papers in this volume were carefully reviewed and selected from 27 submissions. The papers are organized in topical sections on MAS engineering, modeling, and simulation; smart things working together; and innovative and emerging applications of MAS.