Hardbound. This volume begins with two chapters concerned with the chemistry of medium and large heterocyclic rings, including lactones and lactams. This work also explores host-guest relationships within macrocycles embodying oxygen and nitrogen atoms. The authors responsible for bringing together recent progress in the chemistry of this wide assembly of compounds are Dr MacBride and his colleagues Drs Grayson and Kelly. Drs Ewing and McKenzie then survey then survey recent advances in purine chemistry and that of the attendant nucleosides. This chapter naturally leads on to a focused survey of nucleosides and nucleotides. Dr Cosstick contributed a chapter on these major subject areas to the First Supplement and he agreed to review the same subjects in this volume. Professor Pfleiderer is the world's authority on pteridine chemistry and his chapter does more than simply update work on these alkaloids. As a result of his intimate knowledge this author is