What is classical genetics? -- Routes to classical genetics: evolution -- Routes to classical genetics: cytology -- Routes to classical genetics: embryology and reproduction -- Routes to classical genetics: breeding and hybrid formation -- The rise of the American university -- The sex chromosomes -- The rediscovery of Mendelism -- The chromosome theory of heredity -- The predominance of plant breeding to 1910 -- Maize genetics and the popularization of genetics -- Animal genetics in the first decade of the twentieth century -- Morgan and fruit fly genetics -- Forming the fly lab: contributions of A.H. Sturtevant and C.B. Bridges -- Forming the fly lab: contributions of H.J. Muller -- Drosophila genetics after 1915 -- Darwinism, mendelism, and the new synthesis -- Classical genetics to the mid-twentieth century -- Classical genetics and one-celled organisms -- Classical genetics in the service of politics -- Classical genetics and human genetics -- The future and significance of classical genetics -- Classical genetics and the history of science.