Hawk's
Authors' Pseudonyms
by Pat Hawks
No publishing data listed. There are at least three editions. This 2nd edition printed 1995. 1,087 pages. I believe the book was issued without dust jacket, but I'm not sure.
This project had to have been such a massive undertaking that I feel justified in saying it can never really be considered actually finished. Having said that, I don't think anyone can pick up this book and not be extremely impressed with the amount of care that has been given to the thousands of entries.
The book is split into two sections, so you can look up either an author and see his or her pseudonyms, or you can look up the pseudonym and find the author's real name.
As an example, Harlan Ellison has 26 listed pseudonyms, and the entries include the titles of the stories or novels written under each name, which magazine or book contained the story, the date, and whenever possible, who provided the information about the pseudonym. In one of the entries (the name "Cordainer Bird") it mentions that Paperback Parade (#3, page 52) was the source, but it also says that Ellison himself denies using that moniker. You can't get much more detailed than that.