The frugal wizard’s handbook for surviving medieval England by Brandon Sanderson

A man awakes in a clearing in what appears to be medieval England with no memory of who he is, where he came from, or why he is there. Chased by a group from his own time, his sole hope for survival lies in regaining his missing memories, making allies among the locals, and perhaps even trusting in their superstitious boasts. His only help from the ‘real world’ should have been a guidebook entitled The Frugal Wizard’s Handbook for Surviving Medieval England, except his copy exploded during transit. The few fragments he managed to save provide clues to his situation, but can he figure them out in time to survive?