CR2: Book 12 The Hemingway Hoax by Joe Haldeman

In a dive bar, somewhere in Key West, John Baird, a Hemingway scholar meets Sylvester Castlemaine, a con-man. After a brief discussion, "Castle" plants in Baird the seeds of a plot to fool the literary world and make a little money.

Early in his career, Hemingway discovered that several stories he had been working on had been stolen. He had been in Switzerland covering a peace summit for a news service and sent for his lover, Hadley Richardson. On her own initiative, she packed up all his manuscripts (with corresponding first drafts and carbons) in a suitcase, which was then lifted off the luggage cart on the train.
Could Baird, who has absolutely eidetic memory and can remember literally any Hemingway passage "write" these lost stories and pass them off as originals?

Baird takes Castle home to meet his wife Lena and they discuss the plan. A 1921 Corona typewriter would be needed, and retro-fitted with the flaws and quirks to match the machine Hemingway used during that period. And attics all over Paris would have to be searched for the correctly aged paper. And a technique for aging ink would have to be perfected. All sorts of impossible hoops would have to be jumped. Castle wants money, Baird wants the fame.
And that part of the story moves along briskly, and then...

Suddenly on a train, Baird is confronted by an interdimensional being who warns him not to finish the paragraph he was working on. He tells Baird that if he finishes the pastiche, the futures of countless alternate realities are at risk.
This creature, a shapeshifter, is one of a larger group of beings that happens to be...God? The Devil? The Grand Unification Theory? The Great Pumpkin? All of the above and more. It is able to sit still and look over zillions of alternate dimensions and times at once. Every choice any of us makes sends untold branches of causes and effects jutting out into everything. And it's just zeroed in on Baird writing his forgery as the cause of untold fucked-ness.
The creature advises that he will kill Baird if he tells anyone and he has a stick that will give you a heart attack or a stroke or cancer to prove it. Unbelieving, Baird tells a train porter and the universal hitman makes his point a little clearer with a mini-stroke.

Back in Key West, Lena and her newest lover, Castle, plan a wicked double-cross to have Baird blackmailed...

Based on the ridiculous cover art, which features a giant Hemingway face surrounded by several falling, leaping, tumbling Hemingways, I was a little meh about reading this. But once I opened it up, I was in love.
The first act didn't bore me to tears as I imagined it would, and once I realized there was something unmaterialized tracking Baird, my interest kept me involved. The story was as inane as a Nic Cage movie, but well-written with humor and suspense. The Spacio-Temporal Adjustment officer with its dimensional death-cane flutters behind the scenes, moving ghostily through human interaction and was so unexpected at times that I couldn't predict how it was all going to play out.
All in all, a very satisfying read.