Fans of ABC's hit comedy-mystery "Castle" may recall that during this season's premiere, author Richard Castle launched his new book, "Heat Rises," and there was a particularly poignant scene in which detective Kate Beckett expressed her appreciation for the book's dedication.

Credit ABC with a clever twist on franchise merchandising that promotes both its TV series as well as a parallel series of murder mysteries credited to the show's main character, Richard Castle.

Castle is the fictitious character played by actor Nathan Fillion. In the television show's plot, Castle began shadowing detective Beckett, played by Stana Katic, to research his novels. But over four seasons their relationship has evolved well past mentor and mystery writer.

Beckett became Castle's muse, the inspiration for his heroine, Nikki Heat. Beckett's homicide squad is mirrored in Heat's colleagues in the fictional series, which began with "Heat Wave" in 2009 and "Naked Heat" in 2010. Castle's alter ego in the books is author Jameson Rook.

Fans of the television show will enjoy the same well-defined plots and snappy dialogue in the book, including Castle/Rook's signature puns and dark humor. Both put the "pro" in police procedural. The TV scripts and the book's prose are such mirror images that readers can easily imagine Fillion and Katic's voices spouting the lines.

In "Heat Rises," Heat's squad is investigating the death of a parish priest, found bound and tortured in a sleazy New York City bondage club. The cast of suspects includes a notorious drug lord, CIA contractor and an aspiring videographer.

As Heat begins to piece together the trail of clues, it leads her to the New York Police Department. When her questions begin to shake things up, she's ordered to stand down. When she doesn't, she is suspended and stripped of her badge. But that doesn't prevent either Heat or a shadowy crew of assassins bent on killing her from their pursuits.

Perhaps the biggest mystery surrounding the book is its ghostwriter. Who really writes the Nikki Heat series? It has been the source of much speculation on Internet blogs.

Hyperion and Fillion have only divulged that the real author "has appeared on the show." That led fans to assume it was one of the famous trio who made cameos as part of Castle's mystery-writer poker club: Michael Connelly, James Patterson and Stephen Cannell. All three denied credit.

The prime suspect seems to be author Tom Straw, who had a nonspeaking role as an extra at Rick Castle's first TV book signing. Straw is a published mystery writer and began his television writing career in 1985. He gained fame for "Night Court," "Nurses" and "Grace Under Fire."

In what is considered by many to be a sly wink to the author, Castle's books include a fictitious biography stating that Castle "received the Nom DePlume Society's prestigious Tom Straw Award for Mystery Literature." The fictitious society's name is, of course, a nod to "pen name," seeming to point the reader to Tom Straw.

One mystery easily solved: The book dedication Beckett referred to was Castle's eulogy to Capt. Roy Montgomery, the television character who was murdered while defending Beckett in last season's finale. An inclusion just as clever and classy as the series itself.