The Ahab of AHAB'S WIFE is, of course, Captain Ahab of Moby Dick--a book that I have never read. Though assured that I could appreciate AHAB'S WIFE just fine without reading Moby Dick, I did find that AHAB'S WIFE lacked context without Moby Dick to flesh it out, much like The Hours lacked context without the backdrop of Mrs. Dalloway.
This isn't to say that AHAB'S WIFE doesn't stand alone as a novel--it does--but merely that a book about another book, if one hasn't read the first book before reading the second, seems a little off. I've never cared for the whole "book about an obscure character in a classic book" thing much, because it strikes me as somewhat pretentious, as if the second author is accusing the first of leaving something out of the original story. I understand that this isn't always the case, and that some really imaginative books have come from this technique, but I just tend not to like it. I say, if you're writing a story, write your own story. Come up with something new, don't just give us a "fresh" view of a "classic" story.
(The one exception to this, I think, are reinterpretations of Biblical stories. I really love those, because they make me look at the original story in a whole new way, regardless of how many times I've read and reread the story.)
When it was all said and done, I think I did like AHAB'S WIFE. It was a struggle at times, because, for all its lively moments, the book plods along at about the pace you'd expect from a book about a sea captain's wife--waiting and waiting and writing about stuff. The middle two-hundred pages sucked me right in because things actually happened, but the beginning and end took some muscle to get through. To be honest, I didn't care much for Naslund's writing. It was good, sure, but it wasn't my cup of tea, and it took a long time to get used to, though eventually I did and was able to move on in spite of the overly (self-consciously) deep musings she stuck in all over the place.
So, the only problems I had with AHAB'S WIFE were purely personal preferences. Some people would be totally justified in really liking it, and though I ultimately liked it, I can't say I'd recommend it to you.