: In addition to researchers in AI and robotics, RoboCup attracts ordinary people, especially kids, high school and university students. Over 3000 people from 35 nations around the world have participated in RoboCup since the great success of the First Robot World Cup Soccer Games and Conferences, RoboCup-97 [1] held in conjunction with the Fifteenth International Joint Conference on Artificial Intelligence (IJCAI-97). Every year, the number of participating teams is increasing about 50%, that is, 35 teams in RoboCup97, 64 teams in RoboCup-98 [2], and 90 teams in RoboCup-99 [3], and almost same number of teams in RoboCup-2000. Attendance in 2000 was impacted by the application of a new qualification process, difficulties for some of the European teams to travel to Australia, and by the addition of a European RoboCup competition, EURO-2000. This paper focuses on a discussion of the challenging research problems present in RoboCup and how they have been concretely addressed in RoboCup co...