The variation of animals and plants under domestication.

Featuring the first occurrence of the phrase 'survival of the fittest'.
Originally intended as the first two chapters in a larger work on the origin of the species (he viewed the book of that name as simply an abstract of a more substantial project), these were the only ones published in his lifetime. With detailed facts and lengthy discussion, the work includes what Darwin believed to be new ideas of pangenesis, but the topics of sexual selection and human evolution were excluded from these already thick volumes. Despite their size, the works sold briskly (Desmond & Moore, Darwin (London 1991), p.550).

After running through the first issue in just a week (Freeman, p.122), John Murray produced a second issue, with several variations between the two. In the first, the imprint is printed on a single line on the spine, while it is broken on to two lines in the second as Numerous errata also appear in the first issue, most of which were corrected in the second. A second edition of 1875 bears even greater alterations to the text, as well as being reduced in size to a crown octavo.