The Egg Man was a biography done on James Donovan Halliday.
It was mentioned on page 53 while Wade was in his Advanced OASIS Studies class. Wade has read it 4 times, as well as other Halliday biographies.
The title is based on the fact that Halliday created the world's greatest easter egg.
Although there is very little information on it, we do know that it is a best-selling biography on Halliday and that it left out many important details that Wade likes to point out in class.