These are the secrets I have kept. This is the trust I never betrayed.

But he is dead now and has been for more than forty years, the one who gave me his trust, the one for whom I kept these secrets.

The one who saved me...and the one who cursed me.

So begins the journal of Will Henry, orphaned assistant to Dr. Pellinore War throp, a man with a most unusual specialty: monstrumology, the study of monsters. In his time with the doctor, Will has met many a mysterious late-night visitor, and seen things he never imagined were real. But when a grave robber comes calling in the middle of the night with a gruesome find, he brings with him their most deadly case yet.

Critically acclaimed author Rick Yancey has written a gothic tour de force that explores the darkest heart of man and monster and asks the question: When does a man become the very thing he hunts?