The publication in 1859 of Charles Darwin's On the Origin of Species touched off a violent controversy which, when the tumult had died down, left the theory of biological evolution firmly established. The success of the book was instantaneous, partly because the educated public was ready to listen to a reasonable explanation and parly because Thomas Huxley and Herbert Spencer were available and anxious to fight for the theory in the face of all opposition. The opposition was considerable but merely served to fan the flame of public interest. Hence the concept of descent with modification spread and widened and the doctrine of Evolution did more to revitalize human thinking during the past century than any other force. It is for this reason that the Royal Society of Canada commemorated the centenary of the publication of Darwin's book by organizing a symposium on Evolution at its annual meeting in June 1959. This volume consists of papers on geological, biological, philosophical, sociological, and cosmological subjects related to Evolution. Contributors include: L.S. Russell, Vladimir J. Okulitch, M.Y. Williams, Gordon Edmund, Thomas W.M. Cameron, W.P. Thompson, M.J. Dunbar, D.B.A. Savile, Askell Love, R.G.E. Murray, Bruce F. Crocker, le R.P. Louis-Marie Régis, Alexander Brady, H.B. Hawthorn, C.T. Bissell, N.H. Grace, G.M. Shrum, G.M. Volkoff, A.G.W. Cameron. The volume represents a major contribution by Canadian scholars of various disciplines to the world-wide celebration of the Darwin centenary. Royal Society of Canada "Studia Varia" Series, No. 4.