They say of themselves: Welcome to Fantastic Fiction Bibliographies for over 30,000 authors and book information on over 350,000 books. Throughout the site, just click on a book to see its cover picture, description and publication details.
This is a really nice resource - it gives full summaries of each book, and you can see the titles in the correct order. There are links through to similar authors, similar stories, links to second hand online bookshops where you can buy copies of particular books and so on. Of interest to librarians - there are links to librarian jobs, although when I clicked through I was coming up with library jobs in Wales, so I'm doubtful of the value of that particular part of the site.