RoboCup, Robot World Cup, is an international research initiative involving over 20 countries and researchers from various fields surrounding artificial intelligence and robotics. This introductory article describes research programs involved in RoboCup. The goal of RoboCup is to establish a scheme of long-range research, and a series of short-range research goals that essentially converges into the grand challenge as well as creating numerous spin-off technologies. The range of research areas spans from robot hardware design, software and multiagent programming, to natural language systems and education. This article describes how these efforts can be coordinated as an integrative research initiative.