This book constitutes the refereed proceedings of the 23rd International Conference on Principles and Practice of Multi-Agent Systems, PRIMA 2020, held in hybrid mode in Valencia, Spain, in November 2022. The 31 full papers presented together with 15 short papers and 1 demo paper were carefully reviewed and selected from 100 submissions.The conference covers a wide range of ranging from foundations of agent theory and engineering aspects of agent systems, to emerging interdisciplinary areas of agent-based research.

This book constitutes the revised selected papers from the 14th European Conference on Multi-Agent Systems, EUMAS 2016, and the Fourth International Conference on Agreement Technologies, AT 2016, held in Valencia, Spain, in December 2016. The 43 papers and 2 invited papers presented in this volume were carefully reviewed and selected from 68 submissions. The papers cover thematic areas as agent and multi-agent system models, algorithms, applications, simulations, theoretical studies, and for AT the thematic areas are: algorithms