?From time to time a book comes along that cuts a clean swath through a jungle of ideological obfuscation, and illuminates the intellectual scene by rediscovering links that had long been studiously obliterated. Such is Heyer's lucid analysis, not only of the Darwin-Marx connection, but of the dawn of the social sciences, in their relation to the birth of evolutionary theory....We should thank Heyer for rediscovering this fundamental truth of our intellectual heritage, especially now that the very vision of both men, enriched by a century of scientific discoveries, is coming back to the center stage of human self-understanding.?-Pierre L. van den Berghe