First English language edition, originally published as Vorträge über Descendenztheorie in 1902 and here translated from the second German edition of 1904. With the contemporary ownership inscriptions of N. Hollister, likely the zoologist Ned Hollister (1876-1924), assistant curator at the United States National Museum, Division of Mammals, and superintendent of the National Zoological Park (Smithsonian biography).

Freiburg zoology professor August Weismann (1834-1914) is one of the most remarkable figures in the history of genetics, the biologist whose work successfully bridged the period between Darwin's Origin and the rediscovery of Mendel's laws at the turn of the century. Weissmann read the Origin only two years after publication and remained a firm supporter of evolution by natural selection even when other scientists questioned the mechanism by which it acted. Investigating this, he developed the concept of the germ plasm, the idea that the reproductive cells contain a hereditary substance which he correctly located to the chromosomes in the nucleus. He differentiated between reproductive and somatic (body) cells and showed that they did not exchange genetic information, therefore precluding Lamarckism, the inheritance of acquired traits. And he correctly predicted that reproductive cells must contain only half of the genetic material present in somatic cells, so that the combination of egg and sperm creates a single, full set of genetic material.

Weismann published books throughout his career, with The Evolution Theory being the culmination that laid out his whole system in detail and explained its significance for evolution. It was 'an important and widely read book' (EBSCO).

First edition; 8vo; 3 full-coloured plates in volume I, illustrations throughout the text, some with one or two colours, single leaf of publisher's ads at rear of volume I, contemporary ownership inscriptions to the title pages, a few minor pencil notes and marks in the margins, contents faintly toned with a little light spotting to the edges, some darker spotting in the corners of the final leaves of volume I; original red cloth, titles to spines gilt, black coated endpapers, corners bumped, a few light spots to the cloth, cloth and board at the joint of volume II professionally conserved after uneven tearing, a very good set; 416 & 405pp.