Metal chelates are metal complexes - but with properties which may sharply distinguish them from non-chelate complexes. They are almost invariably organometallic compounds - but again their properties are very different from most of the compounds conventionally regarded as 'organometallic'. they may often be formed by quite simple reactions in aqueous solution; so the relevant equilibria can readily be studied and thermodynamic data obtained. The range and variety of chelating ligands are enormous; so, therefore, are the structures of the resulting complexes, and their importance in biological systems and industrial applications is a further consequence of their rich variety. This book, then, is concerned with all these characteristics of letal chelates. They form a distinct area topic in chemistry but one which, because it is contingent upon so many other areas of study, should be of interest to all.