The Monstrumologist series by Rick Yancey

Book one

These are the secrets I have kept. This is the trust I never betrayed. But he is dead now and has been for nearly ninety 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 starts the diary of Will Henry, orphan and assistant to a doctor with a most unusual specialty: monster hunting. In the short time he has lived with the doctor, Will has grown accustomed to his late night callers and dangerous business. But when one visitor comes with the body of a young girl and the monster that was eating her, Will's world is about to change forever. The doctor has discovered a baby Anthropophagus—a headless monster that feeds through a mouth in its chest—and it signals a growing number of Anthropophagi. Now, Will and the doctor must face the horror threatening to overtake and consume our world before it is too late.

 

Book two

While attempting to disprove that Homo vampiris, the vampire, could exist, Dr. Warthrop is asked by his former fiancee to rescue her husband from the Wendigo, a creature that starves even as it gorges itself on human flesh, which has snatched him in the Canadian wilderness. Although Warthrop also considers the Wendigo to be fictitious, he relents and rescues her husband from death and starvation, and then sees the man transform into a Wendigo. Can the doctor and Will Henry hunt down the ultimate predator, who, like the legendary vampire, is neither living nor dead, whose hunger for human flesh is never satisfied? This second book in The Monstrumologist series explores the line between myth and reality, love and hate, genius and madness.

 

 Book three

When Dr. Warthrop goes hunting the "Holy Grail of Monstrumology" with his eager new assistant, Arkwright, he leaves Will Henry in New York. Finally, Will can enjoy something that always seemed out of reach: a normal life with a real family. But part of Will can't let go of Dr. Warthrop, and when Arkwright returns claiming that the doctor is dead, Will is devastated--and not convinced. Determined to discover the truth, Will travels to London, knowing that if he succeeds, he will be plunging into depths of horror worse than anything he has experienced so far. His journey will take him to Socotra, the Isle of Blood, where human beings are used to make nests and blood rains from the sky--and will put Will Henry's loyalty to the ultimate test.