Giles' Manuscript is a document that you can find while doing the Red Harvest quest. After you get Giles' Cellar Key, you can use it to get access to Giles' Cellar. When you get inside, you can find the manuscript in a chest.
Contents of BookEdit
"This appears to be an early draft of Giles' autobiography. Amid the bleak chronicles of his early years as a guard, there is an amusing anecdote concerning a young group of bandits. We'd been tracking their movements for months, and finally got our break. Their leader, a nasty fellow by the name of Ripper, was spotted going into a cave in Bower Lake. We stormed in at nightfall, ready to capture, ready to kill, ready to die. But when we saw what was going on in that cave, we could barely stand for laughing. There they were, the meanest, most bloodthirsty villains in Albion, sharing their latest spoils: chestfuls of frilly dresses, fancy skirts and ladies' underthings. They weren't just wearing their delicate treasures, they were dancing and singing as merrily as any young girls I ever saw. Horrified at being caught like this, they made their escape as we wiped the tears from our eyes. No doubt, they'd be humiliated to have this story told, but I set out to write the truth, and the world has a right to know."