This book constitutes the thoroughly refereed proceedings of the 11th International Conference on Web and Internet Economics, WINE 2015, held in Amsterdam, The Netherlands, in December 2015. The 30 regular papers presented together with 8 abstracts were carefully reviewed and selected from 142 submissions and cover results on incentives and computation in theoretical computer science, artificial intelligence, and microeconomics.

This book constitutes the refereed proceedings of the 12th International Symposium on Algorithmic Game Theory, SAGT 2019, held in Athens, Greece, in September/October 2019. The 25 full papers presented together with 3 invited talks and one abstract paper were carefully reviewed and selected from 55 submissions. The papers are organized in topical sections named: Algorithmic Mechanism Design; Auctions and Markets; Computational Aspects of Games; Network Games and Congestion Games; Social Choice; and Matchings and Fair Division.