The first two novels by the best-selling writing duo of Douglas Preston and Lincoln Child involved Amazonian monsters lurking in the dark recesses of New York's Museum of Natural History.

But a bloodthirsty "museum beast" is humdrum stuff compared with the authors' most outrageous literary creation.

That would be Aloysius Pendergast, special agent for the FBI.

This Southern aristocrat looks like an albino undertaker and has a Holmesian knack for solving macabre crimes that fringe on the supernatural.

"He's not an albino," Child is quick to point out. "Actually, he's just very, very pale."

Fair enough, but that's the only thing about this extraordinary character that is easily explained.

Preston and Child's 12th Pendergast thriller, "Two Graves," is the final installment in a trilogy that weaves together the erudite hero's search for his long-missing wife, Helen; a series of savage New York hotel-room murders; and genetic experiments conducted by modern-day Nazis in the Brazilian jungle.

For those who have been reading all along, "Two Graves" is a pretty tasty reward for your dedication.

"There may be a few dangling threads. Life is like that, after all," Child says. "But there will be nothing left unexplained."

Wrapping up this story also will allow the authors to refresh the series by chucking some excess baggage and venturing into new territory.

The next Pendergast novel, scheduled for publication in late 2013, will be set in a Colorado ski resort, with a plot involving the unlikely link between a serial arsonist and a man-eating grizzly bear.

Over the years, we've learned a lot about Pendergast, a gentleman with refined tastes, surprising physical prowess, mystical deductive powers and a family tree of criminally insane super-villains.

But every riddle explained about this enigmatic soul merely leads to more riddles.

That's what keeps Preston and Child enthusiastically writing about him.

Preston vividly remembers how the character was created in their first collaboration, 1995's "Relic."

"Linc and I were talking about the first few chapters, and Linc complained that I'd written two New York City cops who were exactly the same," Preston says. "He said, 'Why don't we come up with a character who is completely different, a fish out of water?'

"Immediately offended and defensive at this criticism, I snapped back, 'You mean, like an albino from New Orleans?' There was a silence on the other end of the line, and then Linc said, 'An albino from New Orleans. ... Yes, I think we could work with that.' "

Child adds: "He stepped up and shook our hands, a little disdainfully, and said, 'I will be your character, thank you.' No other character we've invented materialized so suddenly and so completely."

Preston and Child seem to be the only writers who know what to do with him, however.

In the 1997 movie adaptation of "Relic," for example, there is no Pendergast to be found.

"Pendergast was in the early version of the 'Relic' script, but he didn't make the final screenplay," Child says. "He was probably just too hard to write, not to mention cast.

"Paramount still controls his character rights in terms of film, and we keep hoping that they will show interest in making a Pendergast movie. We have no idea who to cast.

"To my mind, the young Christopher Walken would have been perfect."

A movie project that is currently in the works is an adaptation of Preston's 2008 nonfiction book, "The Monster of Florence," chronicling the writer's investigation of a 30-year-old serial-murder case in Italy.

"George Clooney is playing the part of me, believe it or not," Preston says.

"Personally," Child says teasingly, "I don't believe it." SUBHEAD: Authors' spat created memorable character

Original Print Headline: Pale Writers