This book contains lecture notes and invited contributions presented at the NATO Advanced Study Institute and EPS Liquid State Conference on PHYSICOCHEMICAL HYDRODYNAMICS-PCH: INTERFACIAL PHENOMENA that were held July 1-15, 1986, in LA RABIDA (Huelva) SPAIN. Although we are aware of the difficulty in organizing the contents due to the broad and multidisciplinary aspects of PCH-Interfacial Phenomena, we have tried to accomodate papers by topics and have not followed the order in the presentation at the meetings. There is also no distinction between the ASI notes and Conference papers. We have done our best to offer a coverage as complete as possible of the field. However, we had difficulties coming from the fact that some authors were so busy that either did not find time to submit their contribution or did not have time to write a comprehensive paper. We also had to cope with very late arrivals, postdeadline valuable contributions that we felt had to be included here. Our gratitude goes to the NATO Scientific Affairs Division for its economic support and to the EPS Liquid State Committee for its sponsorship. Financial support also came from Asociacion Industrias Quimicas-Huelva (Spain), Caycit-Ministerio De Educacion Y Ciencia (Spain), Canon-Espana (Spain), Citibank-Espana (Spain), CNLS-Los Alamos Nat. Lab. (U. S. A. ), CSIC (Spain), EPS, ERT (Spain), ESA, Fotonica (Spain), IBM-Espana (Spain), Junta De Andalucia (Spain), NATO, NSF (U. S. A. ), ONR-London (U. S. A.