The 17th IUPAP International Conference on Thermodynamics and Statistical Mechanics will be held in Rio de Janeiro, Brazil, from July 31 to August 4, 1989. The official language will be English. Limited funds will be available for partial support to participants with considerable financial difficulties. For further information contact the Conference Chairman: Constantino Tsallis, STATPHYS 17, Centro Brasileiro de Pesquisas Fisicas/CNPq, Rue Xavier Sigaud 150, 22290 Rio de Janeiro-RJ, Brazil, Telex (21) 22563 CBPQ BR.