Chiefly contains correspondence concerning Developmental Systems: Insects which Waddington co-edited with Sheila J. Counce (and to which he contributed an essay). The book was published by Academic Press in two volumes in 1972 and 1973 respectively. This material also contains correspondence between Waddington and Counce, some working papers and draft typescripts, including of Counce's Preface. The earlier correspondence deals with projected ideas for other books.