This volume contains the proceedings of the International Winter School on "Heterostructures and Two-Dimensional Electronic Systems in Semiconductors." The school took place in Mauterndorf, Austria, from February 26 - March 2, 1984, and was the third one in a series of winter schools on "New Develop ments in Solid-State Physics," organized by the Austrian Physical Society, Solid State Physics Division. The school was attended by about 150 scientists from 12 countries, including the United States of America, Japan and Poland. Most of the research groups of Western Europe working in this field...