The Pickering Masters Darwin makes it possible for the first time to review Darwin’s public literary output as a whole. Darwin’s works are now presented in their definitive texts, typeset, printed and bound to modern standards. It is important to see Darwin’s literary output as a whole to understand fully both his influence on the religious, philosophical and scientific upheavals of the 19th century, and the development of the theory of evolution which forms a continuous thread running through his work from first to last. This is the fifteenth volume in a 29-volume set (all 29 now available) which contain all Charles Darwin’s published works. Darwin was one of the most influential figures of the 19th century. His work remains a central subject of study in the history of ideas, the history of science, zoology, botany, geology and evolution. Texts have been selected by Professor Barrett and Richard Freeman and where more than one edition of a work exists, the editors have chosen the edition which reflects Darwin’s ideas most fully.