In this volume, the medicinal chemistry of the rapidly expanding family of retinoids, of promising semi-synthetic erythromycins and of the multifaceted amidines is reviewed. Another chapter continues the coverage of inorganic elements which have a medical role; recent studies on the various biological roles of manganese are also examined. Inhibition of enkephalin-degrading enzymes is reviewed, as are studies of the digitalis recognition site which are expected to lead to the development of more highly selective inotropic drugs. This work should be of value to medicinal chemists, pharmacists and pharmacologists. It should also be appreciated by all newcomers, as well as those who wish to be kept up to date with recent work on these topics.