The objective of three-year U.S.-Yugoslav cooperative research project in surface physics between B. Gumhalter, of Zagreb University's Institute of Physics and D. C. Langreth of Rutgers University is to study the fundamental questions on the interaction of atomic particles and radiation with surfaces. Studies in this area are significant because of the role of surface interactions in matter and energy conversion. The project is particularly suitable for joint U.S.-Yugoslav research because of the overlapping interests and expertise of the participating scientists. This project was approved by the U.S.-Yugoslav Joint Board on Cooperation in Science and Technology and is supported through a joint fund consisting of matching contributions from the U.S. and Yugoslav governments. The U.S. contribution is provided annually by the Department of State. No NSF funds are involved. The grants are composed principally of Yugoslav dinars and made to the principal Yugoslav institute. Grants include travel for U.S. scientists to Yugoslavia and a modest dollar allowance for Yugoslav scientists' living expenses in the U.S.