It is impossible in a single volume to deal comprehensively with all classes of secondary plant compounds. In the earlier series of this Encyclopedia emphasis was laid on the isoprenoids and plant phenols. While these compounds have not been neglected in the present volume we have attempted to achieve a more balanced presentation by drawing attention to the importance of nitrogenous secondary metabolites such as the alkaloids, amines and non-protein amino acids. Most of the compounds or groups of compounds included in Volume 8 are of restricted distribution within the plant kingdom and...