This special issue of the International Journal of Game Theory contains a selection of papers presented at the 9th Conference on Logic and the Foundations of the Theory of Games and Decisions (LOFT9), which took place in Toulouse July 5–7, 2010. While this special issue collects papers with a stronger game-theoretic content, a second set of papers that are more logic-oriented can be found in a special issue of the Journal of Applied Non-Classical Logics. The LOFT conferences, which have been a regular biannual event since 1994, are interdisciplinary events that bring together researchers from a variety of fields: cognitive psychology, computer science and artificial intelligence, economics, game theory, linguistics, logic, mind sciences, philosophy, social choice and statistics.