Following S. T. Joshi's acclaimed three-volume variorum edition of Lovecraft's fiction, this final collection includes all known revisions and collaborations undertaken by Lovecraft on behalf of his friends and clients. As with previous volumes in this series, the texts preserved herein scrupulously follow archival manuscripts, typescripts, or original publications, and constitute the definitive edition of these stories. Since Lovecraft's customary procedure as a revisionist was to discard his client's draft and entirely rewrite the story in his own words, much of the fiction in this collection represents original work by Lovecraft, including such notable contributions to the Cthulhu Mythos as "The Electric Executioner," "Out of the Aeons," and "The Diary of Alonzo Typer." Supreme among the revisions in this volume is the brilliant novella "The Mound," which embodies Lovecraft's satirical commentary on the Machine Age "decadence" of his era. For the first time, students and scholars of Lovecraft can see at a glance all the textual variants in all relevant appearances of a story-manuscript, first publication in magazines, and first book publications. The result is an illuminating record of the textual history of the tales, in an edition that supersedes all those that preceded it. S. T. Joshi is a leading Lovecraft scholar and author of H. P. Lovecraft: The Decline of the West (1990), I Am Providence: The Life and Times of H. P. Lovecraft (2010), Lovecraft and a World in Transition (2014), and other critical and biographical works. He has also done significant research on such writers as Lord Dunsany, Ambrose Bierce, Arthur Machen, and Ramsey Campbell.