Letter to Caleb Menge is a book found in Caleb Menge's desk during the quest Count Reuven's Treasure.

"Caleb, I have new instructions regarding the organization of the next execution. When you are ready to meet, place your holy Tome in the drop box located in the column of the Eternal Fire altar in the southwest corner of the Bits. We will meet at the usual spot. Do not tell anyone where you are going and bring no one with you. Burn this letter after reading.