This is the first of a new series of conferences on High Energy Physics to be held at the ICTP on Trieste. The aim of the present Conference is to cover various aspects of physics in 2+1 dimensions, especially (super)membrane theories, and to provide a platform for a discussion of the up-to-date status of the field. There will also be introductory lectures which should be useful, especially to those who wish to begin research in this subject.