The Darwin Correspondence Project, a joint UK-US project based mainly at Cambridge University, has to date published eleven volumes (out of a projected 30) of letters of Charles Darwin. As part of the larger effort, the Project has also produced a calendar of the correspondence of Charles Darwin, an electronic version of which was recently made available at the Project's Website. The online calendar is essentially a catalog with summaries "of all the letters to and from Charles Darwin known to the Project, the full texts of which are being published in the volumes of the Correspondence of Charles Darwin." The Calendar is composed of fourteen separate files, with letters numbered 1 to 13389, dating from October 1846 to April 1882. Users may browse by file, but the letters are not in strict chronological order. Those interested in letters Darwin exchanged with a particular person or institution are advised to use the list of almost 2,000 correspondents, which offers brief biographical descriptions, and the years and calendar numbers of letters to and from Darwin. Users can find out more about the Project and the volumes at its homepage.