I've just discovered something strange. If you leave the book on the floor outside candlekeep you can get in without losing it. You can then retrieve it after you leave. Here's the downside... You can't use it to get back in. The game lets you in when you reach the right stage in the game; not when you have the book. (For anyone who cares, if you identify it, it is 'History of the Nether scrolls').

why would you want to retrieve it though? Theres nothing worth going back into candlekeep for!

candlekeep is yust boring !

no people to fight, no big quest and no good merchants.

why go back when we have baldurs gate ?