Charles Darwin's health improved substantially in 1866 under a dietary and exercise regime prescribed by his physician Henry Bence Jones. With renewed vigour, he worked steadily on his manuscript of Variation of Plants and Animals under Domestication, submitting all but the final chapter to his publisher in December. He also worked on the fourth, and much revised, edition of Origin which was delivered to printers in July, and preparations were begun for a third German edition of Origin. His improved health allowed him a more active social life. At Down, Darwin entertained a number of scientific colleagues whom he had known previously only through correspondence. He also made his first appearance in London scientific society in many years, touring the Zoological Gardens at Regent's Park, and appearing at a soiree at the Royal Society.

Volume 13 contains letters for 1865, the year Charles Darwin published his long paper on climbing plants and continued work on his book, The Variation of Plants and Animals under Domestication. 1865 was also the year when Robert FitzRoy committed suicide; Joseph Dalton Hooker became director of the Royal Botanic Gardens, Kew; and Charles Lyell and John Lubbock quarrelled over an alleged incident of plagiarism. The volume includes a supplement of over 100 letters discovered or redated since the series began publication, including a fascinating collection written when Darwin was 12.

Charles Darwin is a towering figure in the history of science, who changed the direction of modern thought by establishing the basis of evolutionary biology. With a Foreword by Sir David Attenborough, this is a fascinating insight into Darwin's life as he first directly addressed the issues of humanity's place in nature, and the consequences of his ideas for religious belief. Incorporating previously unpublished material, this volume includes letters written by Darwin, and also those written to him by friends and scientific colleagues world-wide, by critics who tried to stamp out his ideas, and admirers who helped them to spread. They take up the story of Darwin's life in 1860, in the immediate aftermath of the publication of On the Origin of Species, and carry it through one of the most intense and productive decades of his career, to the eve of publication of Descent of Man in 1871.