Originally published in 1986, we were living in a world in which the number of publications in behaviour genetics had reached a point where it was difficult, even for those teaching the subject, to keep up with the literature. The editors of this title believe that there is a need for people who have planned and executed long-term research programs to summarize and comment on their results. This volume was intended to help meet that need. The authors were given free choice of subject and format. The result is a variety of topics that had been researched mainly over the previous decade. Chapter 1 is an exception and looked back at the work of others in behaviour genetics over a quarter-century and tried to detect trends in the types of research done in the field.