“Mr. McMahon’s inventive, eventful, smartly written Head Cases, with its brilliant but fallible protagonist, its twisted-minded perpetrator, and its mix of sentiment and intrigue, is a terrific debut that augurs well for further installments in the series.” –The Wall Street Journal

"A stellar new series...Head Cases balances fully fleshed-out, quirky characters with McMahon's fine eye for details about the inner workings of investigations coupled with methodical plotting...McMahon's precise storytelling in Head Cases should assure many adventures with this intelligent team."—Oline Cogdill, South Florida Sun Sentinel

“In this suspenseful cat and mouse thriller, Camden balances brilliance with a deeply flawed awareness of social cues, retaining the edge of a compelling protagonist. This, combined with McMahon's gripping plot, will pull readers in.”—Booklist

“McMahon introduces several clever wrinkles to this classic cat-and-mouse setup, while making the socially awkward Camden and his colleagues three-dimensional enough to sustain future installments. With pulse-pounding action and enough surprises to blindside even seasoned mystery fans, this is an excellent start.” –Publishers Weekly (Starred review)

“A superior cat-and-mouser, with both parties armed to the teeth.”–Kirkus Reviews

"A must for your TBR pile."—FirstClue

“A twisting FBI procedural with a cool cast of characters… I was in heaven… Not only because there’s more than one serial killer, but I also loved that the PAR agents don’t play well with others.” –Minnesota Star Tribune

“Fast paced… a thrilling conclusion… gives good reason to get attached to the characters…” –St. Louis Post Dispatch

"Both meticulously plotted and populated by offbeat characters, Head Cases is a series debut that readers will be talking about all year long...Gardner Camden is sure to become a fan favorite... As this is the launch of a series, watching his evolution—not just as an FBI agent, but as a human being—will be the reason readers return for case after case."—BOLO Books

"Head Cases begins as a riveting story about the hunt for an apex predator—a killer of serial killers—but quickly becomes so much more: the only road back to what’s left of one man's family, friendships, and identity. It’s a taut, thrilling read.” —Jess Lourey, Edgar-nominated author of The Taken Ones

"Grabbed me from page one!" – J.A. Jance

“John McMahon's Head Cases is everything this crime fiction-lover could want: gripping, twisty, and atmospheric, with a harrowing and intriguing plot, gorgeous prose, and fresh and compelling characters. McMahon doesn’t just knock the ball out of the park with this one—he sends it flying into the next universe. I sincerely hope this is the beginning of a new series because I want more!” – Karen Dionne, author of the #1 international bestseller The Marsh King's Daughter and The Wicked Sister

"I couldn’t get enough of this addictive, propulsive story of intellect and intrigue. Head Cases is a masterfully-done game of cat and mouse with an unforgettable cast of characters." —Matthew Quirk, New York Times bestselling author of The Night Agent