Will Henry and Dr. Warthrop have encountered many horrors together—but can Will endure a monstrumological terror without his mentor? Will Henry has been through more that seems possible for a boy of fourteen. He’s been on the brink of death on more than one occasion, he has gazed into hell—and hell has stared back at him, and known his face. But through it all, Dr. Warthrop has been at his side. When Dr. Warthrop fears that Will’s loyalties may be shifting, he turns on Will with a fury, determined to reclaim his young apprentice’s devotion. And so Will must face one of the most horrific creatures of his monstrumology career—and he must face it alone. Over the course of one day, Will’s life—and Pellinor Warthrop’s destiny—will lie in balance. In the terrifying depths of the Monstrumarium, they will face a monster more terrible than any they could have imagined—and their fates will be decided.

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 threatenning to overtake and consume our world before it is too late. The Monstrumologist is the first stunning gothic adventure in a series that combines the spirit of HP Lovecraft with the storytelling ability of Rick Riorden.

While attempting to disprove that Homo vampiris, the vampire, could exist, Dr. Warthrop is asked by his former fiancé 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.