Barack Obama will be the 11th American president to hold office since Fidel Castro and his comrades triumphantly entered Havana 50 years ago this month.

Since then, it's fair to say that the great dictator has held generations of U.S. policymakers in reactive thrall. Efforts to assassinate or overthrow him have failed. The Missile Crisis brought America and the Soviet Union as close as they ever came to nuclear war. Generations of economic cold war have failed and so has Communism.

		"FIDEL'S LAST DAYS: A NOVEL" By Roland Merullo Shaye Areheart Books ($23)

In the meantime, the so-called Cuban model grinds along as one of the world's most perplexing societies. Cuba can't feed itself or even grow enough sugar to supply its own market. It has a thriving biotech sector and hospitals open to foreigners willing to pay for organ transplants or other expensive treatments, but its scientists and surgeons can't adequately feed their own families.

A lot of Cubans cannot imagine a future without Fidel, now 82 and ailing. He lingers like a ghost in pajamas, still powerful but unseen, while day-to-day power in a nation theoretically run according to the dictates of scientific socialism has passed through the crudest of antique mechanisms -- dynastic succession -- to his 77-year-old brother, Raul.

If Soviet Russia was, as Winston Churchill famously described it, "a riddle wrapped in a mystery inside an enigma," Communist Cuba is and has been a melodrama shrouded in paradox.

That ought to make for compelling fiction, the sort that might be approached in a particularly fascinating way through the thriller genre. That's certainly what Roland Merullo had in mind with his tightly plotted but ultimately unsatisfying fiction concerning an elaborate conspiracy to kill Castro.

Merullo is a prolific author, whose best-known book is probably the fable "Golfing With God," which envisioned heaven as a villa alongside a celestial fairway.

Here, he has come up with a promising structure. The taut and intricate narrative is essentially built around a daughter of Cuban American emigres and a conflicted member of Castro's inner circle.

Carolina Perez is a one-time CIA operative, now deeply under cover and enmeshed for five years in a powerful and secretive organization, the White Orchid, whose goal is the dictator's assassination.

A fellow conspirator broods in Havana. Carlos Gutierrez, Cuba's minister of health, has become a silent dissenter and has resolved to act, which leads him and his family, particularly his anguished wife, into deep peril.

He and Carolina will meet in the most difficult imaginable circumstances as the plot builds to a breakneck but oddly surprising conclusion in a series of final chapters that adopt the unfortunate and overused device of proceeding in clipped and abbreviated form.

Among the drawbacks is that Merullo's evocation of contemporary Cuba doesn't measure up to either the reality or the drama of the headlines.

The best that can be said of the novel is close but no cigar, and, certainly, not a Habana.