The story is quite contrived, like those action movies that compromise the suspension of disbelief with repeated strokes of luck or well-timed misfortune for the hero.
I recommend reading it, anyway. Why? Because the writing is excellent. The mechanics of narrative and character development are so well executed that merely reading through once leaves on with the impression that a few valuable lessons have been served. The best way to learn writing, after all, is reading the works of those who are better at it than yourself.
More than well executed, though, the work is beautiful. Nearly every page offers a new simile or metaphor that accomplishes chapters worth of storytelling in a few sentences. Many of the sentences themselves are so packed with meaning and beautifully paced they beg to be bookmarked or copied for future reference.
Now, if Helprin would just choose a less hackneyed subject