This manual collects in the form of laboratory protocols a series of experiments in the field of Membrane Transport and Membrane Bioenergetics. It represents the experience accumulated during four advanced courses held at the Depart ment of Biochemistry of the Swiss Federal Institute of Technology on behalf of Federation of European Biochemical Societies (FEBS) in the years 1975 through 1978. The idea of collecting the experiments into a laboratory manual developed as a response to a demand from the students who took part in the courses. Further motivation came with the fmding that, in planning the laboratory sessions, the teaching staff had no organized, modern source of information in the literature. The experiments presented cover most areas of importance in the subject mat ter. Their presentation has been continuously modified in the course of the four years during which the manual took shape, to accommodate to experience and various suggestions. In their present form, all of the experiments described have been repeatedly practiced to optimize their execution. Efforts have been made to combine in the manual classical experiments, and techniques which require relatively unsophisticated instrumentation and can therefore be carried out in most laboratories, with more modern experiments and relatively newer technol ogies. In its present form, the manual should therefore provide a usefui tool in the hands of researchers and laboratory teachers at different levels of sophisti cation and instrumentation.