The Austrian biologist Paul Kammerer was an outspoken proponent of the theory of inheritance of acquired characteristics (Lamarckism) during the time in which Mendelian theory was becoming deeply entrenched in biology. His major research efforts, straddling the First World War, centered on experiments performed on salamanders and on the midwife toad, and seemed to provide empirical support for a Lamarckian mechanism in evolution. He also developed a monistic "law of seriality," in which he attempted to explain coincidence as the product of a higher order natural law. A Socialist, Kammerer was widely regarded as a brilliant scientist, but for scientific, personal, and political reasons, he engendered as much antagonism as support, preventing him from ever obtaining a regular university appointment. His career ended tragically in allegations of fraud, followed by his suicide. The Kammerer Papers is comprised of photocopies of materials that document the brief, but controversial career of a non-Darwinian evolutionary biologist. The bulk of the collection consists of photocopies of articles by Kammerer, often from obscure newspapers or periodicals, along with a small number of letters to his friend Hugo Iltis, the geneticist and biographer of Mendel. Nearly all of these pertain to the Kammerer's experiments with amphibians to test Lamarckian inheritance or to his other biological theories. The collection also includes a small number of items dating from after Kammerer's death, but relating to his life and work, including two letters from his former supervisor Hans Przibram, a letter from Hugh Iltis (Hugo's son) to Arthur Koestler and the reply, and a brief biographical reminiscence of Kammerer written by Hugo Iltis.

One of the most important natural historians in nineteenth century Britain, Charles Darwin provided the first compelling mechanism to account for organismal evolutionary change. Although lacking a coherent model of heredity, Darwin's natural selection has exerted an enormous influence over the biological sciences and since the introduction of Mendelian genetics, had remained the key unifying principle in the discipline. The APS Darwin Papers are a large a valuable assemblage of Darwin's correspondence with scientific colleagues, including Charles Lyell and George J. Romanes. They are included in the print version of the Correspondence of Charles Darwin (Cambridge Univ. Press).