Alternate history, when properly handled, can be entertaining or riveting, and occasionally both.

Some writers start with history having been changed already and then create an entirely different — and usually malevolent — world. In The Plot Against America, Philip Roth imagines an America in which isolationist Charles A. Lindbergh defeats FDR for the presidency in 1940 and reaches an accommodation with a triumphant Nazi Germany.

Others don’t alter history, but create stories that tweak known facts and describe failed plots, which, had they succeeded, probably would have distorted history. In the classic British thriller Rogue Male, Geoffrey Household’s protagonist stalks and then tries to shoot an unnamed European dictator (undoubtedly Hitler) with a hunting rifle. What’s good for the goose is apparently good for the gander: In Jack Higgins’ The Eagle Has Landed, Nazi paratroopers land in England and with the help of what must be considered a shortsighted IRA try to kidnap Winston Churchill so Hitler can win the war.

(An aside: While alternate-history literature has encompassed many epochs, from Jurassic days forward, and is a staple of science fiction, it’s obvious that the genre — not to mention Hollywood — found a gold mine in the Nazis. Alternate-history novels about the failure of the New Deal’s Works Progress Administration just wouldn’t cut it.)

Which brings us to the fine novel being reviewed here, Fear Itself, by Andrew Rosenheim, which details a failed Nazi (of course!) plot to assassinate FDR in the scary days prior to World War II.

The story kicks off in 1936 in Austria and winds up in a politically connected socialite’s house in Washington, D.C. What makes Fear Itself (the title is taken from FDR’s famous inaugural speech) so interesting is that its protagonist is a loyal German-American FBI agent whose Jewish boss has him infiltrate the Bund, a fascistic American organization that promulgated pro-Nazi propaganda and political activities. The agent, Jimmy Nessheim, uncovers more than he bargained for and is drawn into a Washington orbit that includes Lucy Mercer Rutherford, FDR’s alleged mistress, as well as J. Edgar Hoover and his second-in-command, Clyde Tolson. (Many people believe Tolson was Hoover’s Rutherford, in a manner of speaking).

Throw in a mysterious British diplomat/secret agent, pro-Nazi relatives, duplicitous FBI colleagues and a Nazi assassin code-named “Dreiländer” (to name but a few of the novel’s cast of characters) and fledgling Agent Nessheim has his hands full. Fear Itself is billed as the first of a series of books featuring the young Nessheim. So it will be no spoiler to mention that he survives this novel, although there are several close calls, including one at sea that is truly hair-raising.

Rosenheim’s descriptions of the late 1930s are spectacular, and obviously the result of prodigious research (or else Rosenheim is 100 years old and blessed with an incredible memory). In addition to those luminaries mentioned above, other historical figures, some good, some evil, pop in and out of the narrative. It would not be a stretch to suggest that modern readers, especially young ones, can get a fairly accurate picture of Depression-era America in the pages of this book.

As a thriller, Fear Itself does have flaws. The plot is overly complicated. There’s not enough sex and humor to make some of the main characters interesting. (Not that anyone wants to watch either the FDR-Rutherford or the Hoover-Tolson relationship being consummated!) But some of the other players, from Nessheim on down, should be having a little more fun. After all, there is a world war looming.

Of course, the same could be said about a lot of current thrillers that, while bloody, are often bloodless. At least Fear Itself is masterfully written and, as such, is a cut above most of the un-thrilling books called thrillers nowadays.

Lawrence De Maria was a senior editor and writer at the New York Times and Forbes. His many front-page articles led the Times’ Pulitzer Prize-nominated coverage of the 1987 stock market crash. De Maria lives in Naples, Fla., where he writes novels and short stories, is a film and book critic, and lectures on financial journalism. His first novel, Sound of Blood, and his four subsequent novels are available through his website, www.lawrencedemaria.com.