The present volume considers the most recent developments in the chemistry of cyclic inorganic and organoelement compounds. Nineteen of the 22 chapters are based on invited and other lectures presented at the 6th International Symposium on Inorganic Ring Systems held in Berlin on August 18-22, 1991.Main group compounds dominate the content from boron via carbon, silicon, germanium, tin, nitrogen, phosphorus and arsenic, to sulfur and selenium. The book is organized by element, moving from left to right in the main groups of the Periodic Table, followed by one chapter each on bonding and nomenclature of ring molecules. The list of contributors comprises distinguished scientists from 8 countries.