This is the third volume of the complete edition of The Correspondence of Charles Darwin. For the first time full authoritative texts of Darwin's letters are available, edited according to modern textual editorial principles and practice. The letters in this volume were written during the years 1844-6. By 1844 Darwin had become an established figure within the circle of London naturalists and his life at Down had assumed the regularity that the responsibility for a thriving and growing household entailed. Despite his move to rural Kent, Darwin was not isolated, and this volume shows how frequent were his trips to London and further afield, how regular his meetings with his scientific colleagues, and how extensive his network of correspondents.