Leo Marks's Between Silk and Cyanide: A Codemaker's War 1941-1945, a June release from Free Press, is in that limbo between being released and awaiting reviews from major consumer media.

But that's about to change.

In the coming weeks, the book is set to be reviewed in both the daily (at press time, scheduled for July 21) and Sunday New York Times, as well as in the Washington Post's Book World. And perhaps better yet, Times reporter Mel Gussow met the 70-something Marks when the first-time book author was here from the U.K. on a quick New York and D.C. tour and was inspired to do a full profile, which ran July 18.

But sales of Between Silk and Cyanide, working from a 25,000-copy first printing, are already building through word of mouth. Without any co-op push, Amazon.com featured the book on its home page, propelling it at one point to #5 on Amazon.com's Hot 100, and making it Free Press's top-selling book online that week. Amazon.com also plans to e-mail a follow-up profile to selected customers.

And on his brief recent tour Marks already made his mark: he sold out a Smithsonian event for his book -- some 270 tickets at $13 each.

"What's driving this book is not that people know who Leo Marks is, but that there are definitely people fascinated by codes," said Free Press associate editor Chad Conway, who acquired the book last fall from HarperCollins U.K, which is currently on its third printing of the book. "And many have just rediscovered the topic of World War II."

Marks's memoir is an incredibly dramatic first-hand look at the workings of the Special Operations Executive (S ), the intelligence division responsible for creating code so that Allied agents, working within Nazi-occupied territories, could report back. (Most published accounts concern the breaking of the Germans' Enigma code by the British Intelligence's cryptographic department at Bletchley Park.)

PW readers will be pleased to know that Marks actually broke his first code in a bookstore -- he figured out his father's secret pricing system in his antiquarian bookshop Marks & Co., located at 84 Charing Cross Road. (Yes, that's the store immortalized by Helene's Hanff's novel, and the subsequent play and movie. )

Marks took his know-how to the S , where, while still only in his early 20s, he promoted the idea of printing one-time-only code (in invisible ink, of course) on a tiny piece of water-soluble silk, a thin fabric that could possibly escape detection if an agent were searched. Marks felt that it was actually better not to memorize code in case the agent was tortured.

Prior to this breakthrough, Marks has suggested that the operatives' usual code -- using well-known p ms -- should be replaced by original p ms that are not as easily deciphered. "I guess people picked these p ms to at least get use out of them after the horror of having to learn them in school," said Marks, with the kind of irreverent humor that also characterizes his book.

The book is full of the p ms Marks and others created -- some humorous, some obscene. One is particularly haunting: Marks"s "The Life That I Have," a p m he originally wrote for a lost love, was given to agent Violette Szabo shortly before her detection and execution. "The Life That I Have" often appears on British lists of most-loved p ms. But, Marks said, "To me, they're not p ms, they're just codes."

Perhaps, but after the war, Marks crafted a writing career, most notably penning the screenplay for Peeping Tom, a 1960 serial-killer film that at the time was reviled by critics, effectively destroying director Michael Powell's career. It now has cult status, adored by such film directors as Brian DePalma, who used it as inspiration for Raising Cain, and Martin Scorsese, who gave the film a theatrical re-release earlier this year. Scorsese also gave Marks perhaps his most unusual gig: he is the voice of Satan in the director's controversial The Last Temptation of Christ.

Marks is now considering writing a screenplay incorporating incidents from his memoir. PW proposes that Marks should at the very least narrate an audio of the book, to put that devilishly good British diction to fine effect. He demurs, however, saying he is simply pleased to have in print all the humor and pathos of S . Perhaps the greatest tragedy sprung from the messy bureaucratic infighting, which effectively led to the destruction of the Netherlands' resistance movement. Marks suspected that the Germans had cracked the code there but couldn't convince his superiors; the Germans relayed false messages that sent many agents to their deaths. The German intelligence mastermind in Holland ultimately sent a mocking message thanking S for "our long and successful cooperation as your sole agents."

"I had to tell the story now or take it with me," said Marks. Indeed, Marks is very aware that most of his adventures in this world are behind him. "I am now pondering the ultimate indecipherable," he said.