Living Greyhawk Redux
A Comparative History of Ur-Flan and Modern Magicks
A tome on the history of magic
If consulted for at least 10 minutes, this book grants a +2 circumstance bonus to Knowledge (Arcana), Knowledge (History) and Knowledge (Religion) checks. It also allows you to retry a failed check of one of those skills by spending an hour referencing it. Only one retry is allowed.
Valued at 2500 gp