London: John Murray, 1868. FIRST EDITION. Original Cloth. Very Good. FIRST EDITION, FIRST ISSUE IN ORIGINAL CLOTH of Darwin's sequel to the Origin of Species, including his first use of the term "survival of the fittest". "The Variation was a full statement of the facts on which the theories of the Origin were based... "After the Origin's publication Darwin embarked on two broad lines of research: botanical experiments, and studies of variation, sexual selection, and emotional expressions in humans and mammals. In 1860 he began recycling the early, as yet unpublished, chapters of 'Natural selection' and studying the osteology of domestic pigeons, ducks, and geese for a book on how breeders and horticulturists modify species. This was The Variation of Animals and Plants under Domestication (1868)... Its two volumes were intended to provide overwhelming evidence for the ubiquity of variation, although they would also incidentally answer Lyell and Gray, who maintained that…