The theme of this book is the appropriate methodology for the study of the history of life on earth. In particular, it focuses on the interplay between form and structure -- the things that we might predict and model - and the things that we cannot predict -- the arbitrary and the contingent -- which may be as important, or even more so, than the way in which life on earth has evolved.

The contributors are drawn from the disciplines of palaeontology, archaeology, anthropology and human evolution; the timescales covered are from the development of life on earth, through human evolution, to later prehistory and historic archaeology. Underpinning the theme of the book is the work of Stephen Jay Gould, who has developed a distinctive philosophy of history concerning the nature of long-term and short-term evolutionary processes, particularly stressing the interplay between structure and contingency.