The Fourth Latin-American Symposium on Surface Physics (SLAFS 4) was held from July 14 to 18, 1986, at the Unversidad Central de Venezuela, Caracas, Venezuela, as part of a program of the Centro Latinoamericano de Fisica (CLAF) aimed at improving the scientific relations and coop- eration among Latin-American researchers in the field of surface physics. This symposium, which brought together about 60 scientists, included 12 invited talks given by internationally recognized experts covering a wide range of surface physics topics and showing the most recent develop- ments of the theory and spectroscopies involved. This proceedings volume contains the text of the 12 invited lectures plus a selection of the Latin- American contributed papers. The topics covered during the conference were: thin films, chemisorption theory, and surface spectroscopies such as high resolution electron energy loss spectroscopy (HREELS), inverse pho- toemission, Auger deexcitation, SEXAFS, LEED, Raman spectroscopy (SERS) and deuteron solid state FT-nuclear magnetic resonance spec- troscopy. There were also some contributions related to the application of surface analysis to the chemical and semiconductor industries. In addi- tion to the talks there were two poster exhibitions, which showed mainly Latin-American contributions, making it possible to discuss extensively the work presented. Finally, we wish to acknowledge the assistance given by the local or- ganizing committee, especially the diligent cooperation of Luis Cortina, Ivan Escalona, Helena Isern, Miguel Martin, Claudio Mendoza and Ivar Pettersson in developing the symposium program.