Ramsey Campbell, one of the premier horror writers of the English-speaking world, is now 75, and has recently entered his seventh decade as a published writer. This is quite literally true. His first book, a collection of Lovecraft-inspired tales called “The Inhabitant of the Lake,” appeared in 1964, when its fledgling author was still in his teens. In the years since, he has produced a steady stream of novels, novellas and stories. Taken together, they constitute one of the monumental accomplishments of modern popular fiction.