A theme common to the newly written articles presented in this volume is that demographic theory has lost touch with the reality of its data. The purpose of the book is therefore to marry mathematical rigour with sociological and social awareness to improve both the theory and its application. The contributors Esther Boserup, David Coleman, Nancy Howell, Philip Kraeger, Stephen J. Kunitz, R.D. Lee, R.J. Lesthaeghe, Roger Schofield, Richard Smith, J. Simons, Richard Stone, G.N. von Tunzelmann, E.A. Wrigley.