More help for the online researcher.
The ever-helpful OCLC WorldCat has rolled out a beta version of its Author Identities project. These entries provide a rundown of an author's life and works, the most frequently held works of the author by the world's libraries, links to related names and subjects in the author's life, and even cover art.
Take a look at these sample pages on Edgar Allan Poe, Arthur Conan Doyle, and Isaac Asimov.
Also from OCLC: The top 1000 titles held by the world's libraries (The top mystery work? The Adventures of Sherlock Holmes, at #192).