Announcement Reinforcement learning (RL) is a growing research area. To build an European RL community and give visibility to the current situation in the old continent, we are running a now biennal series of workshops. EWRL-1 took place in Brussels, Belgium (1994), EWRL-2 in Milano, Italy (1995) and EWRL-3 in Rennes, France (1997). EWRL-4 will take place in Lugano, Switzerland (1999). The first morning will feature a plenary talk by Dario Floreano. The rest of the two-day workshop will be dedicated to presentations given by selected participants. Presentation length will be determined once we have some feedback on the number of participants. The number of participants will be limited. Access will be restricted to active RL researchers and their students. Please communicate as soon as possible, and in any case before August 15, 1999, your intention to participate by means of the intention form attached below (e-mail is preferred: mdorigo@ulb.ac.be). Otherwise send intention forms to: Marco Dorigo IRIDIA, CP 194/6 Université Libre de Bruxelles Avenue Franklin Roosvelt 50 1050 Bruxelles Belgium An inscription fee of CHF 300 (roughly $200 at current change) will cover local organization expenses, coffee breaks, and a social dinner.