Chapter headings. Preface. Naturally occurring cyclobutanes (T.V. Hansen, Y. Stenstrøm). Diels-alder reactions in the synthesis of higher terpenes (T.J. Brocksom et al.). The asymmetric synthesis of unnatural &agr;-amino acids as building blocks for complex molecular synthesis (M.G. Natchus, X. Tian). The role of organic synthesis in the generation of molecular diversity (D.L. Wright et al.). Biographical sketches of the contributors. Index.