RoboCup 2004 : Springer : 9783540250463 : 3540250468 : 23 Mar 2005 : ThesearetheproceedingsoftheRoboCup2004Symposium,heldattheInstituto Superior T' ecnico, in Lisbon, Portugal in conjunction with the RoboCup c- petition. The papers presented here document the many innovations in robotics that result from RoboCup. A problem in any branch of science or engineering is how to devise tests that can provide objective comparisons between alt- native methods. In recent years, competitive engineering challenges have been established to motivate researchers to tackle di?cult problems while providing a framework for the comparison of results. RoboCup was one of the ?rst such competitions and has been a model for the organization of challenges foll- ing sound scienti?c principles. In addition to the competition, the associated symposium provides a forum for researchers to present refereed papers. But, for RoboCup, the symposium has the greater goal of encouraging the exchange of ideas between team