The RoboCup Challenge-97 offers a set of three fundamental challenges, focused on learning, real-time planning, and opponent modeling. Learning and real-time planning of multi-agent systems were chosen as the first set of challenges because they are essential technical issues for RoboCup, as well as for general AI systems using a multi-agent approach. Together with the physical agent challenge, these challenges will be be a basis for the RoboCup Challenge-99, and for longer research enterprises.