Gillian's Diary is a two-part tome in Act I of Diablo III. Both parts are needed to complete the achievement A Quick Study. Each part can be found in a lockbox to the right of the first house on the Old Tristram Road, or in The Old Ruins. The lockbox holds different books, so this one may not spawn the first time.

They read as follows:

Part 1Edit

"Ogden and his wife have offered to let me and Grandmother continue to stay with them. I think we will now that the troubles are over.
I am still tormented by horrific nightmares. I keep hoping they will fade, but they seem to be getting stronger.

Part 2Edit

"To think I was once afraid of Adria. She is going to take me to Caldeum! I never thought to see it with my own eyes...
Thought it saddens me to leave Ogden and his wife, Adria assures me that she will find a cure for my nightmares.
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