Introduction. The starting point: Evolution versus Creation? The Origin of Life. THE FIRST CIRCLE. Early theories: Creation, Pre-formation and Order in the Biological World. More Theories. THE SECOND CIRCLE. Georges Cuvier and the Theory of Catastrophes. Etienne Geoffroy Saint-Hilaire: The Theory of Comparative Anatomy. Jean Baptiste Lamarck: The Theory of Descent. Charles Lyell: "The Father of Geology". THE THIRD CIRCLE: CHARLES DARWIN, HIS THEORY, HIS SUPPORTERS AND ADVERSARIES. Charles Darwin: The Formative Years. Evolution of the Theory of Natural Selection. On the Same Track: Ideas about the History of Life before 1859. Alfred Russell Wallace. Thomas Henry Huxley. Louis Agassiz: Classification and the Plan of Nature. The Struggle for Existence of the Theory of Evolution. Charles Darwin: "The Descent of Man" (1871). Charles Darwin, "Sexual Selection". Charles Darwin in the Vegetable Kingdom. Heredity in the 19th Century: What did Darwin know? Ernst Haeckel: Embryology and Phylogeny in Evolution. August Weismann: The Theory of the Germ Plasm and the (Non)-Inheritance of Acquired Characters. Francis Galton: Quantitative Measurements of Heredity. The Biometricians: Karl Pearson. THE FOURTH CIRCLE: THE THEORY OF EVOLUTION IN THE 20th CENTURY. Gregor Mendel and the Origin of Genetics. Hugo de Vries and the Theory of Mutations. T. H. Morgan: Drosophila, Genetics and Evolution. The Resurrection of the Inheritance of Acquired Characters: from Weismann to Lysenko. Genetics in Populations: An Introductory Overview. R.A. Fisher: The Fundamental Theorem of Natural Selection. J.B.S. Haldane: Science in Everyday Life and Genetics in Populations. Sewall Wright: Chance and Evolution in Small Populations. Theodosius Dobzhansky. Ernst Mayr: The Biological Species and Speciation. Julian Sorrel Huxley. Richard Goldschmidt (1878 1958): Genetics, Evolution, and Hopeful Monsters. E.B. Ford and H.B.D. Kettlewell: Ecological Genetics. Motoo Kimura and the Neutrality Hypothesis. Closing comments.