I am taking a cleric from BG1 through BG2/ToB.
I have heard rumors that 3 Tomes of Wisdom exist with TOTSC.
I have only found 2 (Durlag's Tower and in Candlekeep's tombs)
Could anyone tell me if a third one exists, and if so, where to find it?
Thanks in advance.

AR0600: Lady's House; ask Chanthalas Ulbright after having quest to get this book. Offer him 500 golds and he gives this book for nothing.

This tome belongs to the geas quest however.

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I have always used the tome to satisfy that quest. But reportdely you can choose the dialogue option where you lie that you don't have the tome and she attacks you. You can then kill her for 6000 XP without any loss of rep or fallen status for a paladin. You'll have to fight her faithful as well as her of course.

Yes, I did what Lemernis did. But I pickpocketed the tome. Anyways, i couldn't stand her, and her faithful "the bitch queen, brooks no insolence" So annoying, but feels so good to kill, especially if you chunk her....

<font color="cyan">I gained the tomb, by purchasing it for 500GP. I then told the "bitch" that I didn't have it, and she attacked me. Easy fight, sweet EXP!</font>