Genes exist predominantly as families with related structures and functions, particularly within eucaryotic organisms. The isozyme concept was first introduced by Markert and MØller in 1959, and has formed the basis of large numbers of scientific investigations and conferences on gene families since that time. This volume is based on presentations made by invited Plenary and Symposia speakers at the Eighth International Congress on Isozymes on the topic of Gene Families: Structure, Function, Genetics and Evolution. The major themes for the Congress were in the following areas: molecular evolution; population genetics; enzymology; Australian fauna; biomedical aspects; molecular genetics; cellular compartmentation; gene regulation; and developmental genetics.