Let me preface this by saying that I'm a huge Michael Crichton fan. My bookshelf is crowded with Crichton books, and I count Jurassic Park and Timeline among some of my favorite books. I may be a bit biased. I won't say that Pirate Latitudes is a great book, but I will say that it was OK.
Now, if you're like me and have read Crichton's other works, you'll be surprised at the lack of science and intrigue. The novel is set in the Spanish controlled Caribbean during the 1600s, and follows the exploits of a British colony and it's menagerie of rogues. The reader is first introduced to the governor of the Jamaica colony, Sir James Almont, who plays a large role near the beginning of the book. He's is not much of a redeeming character, and the first few chapters of the book drag as a result.
Soon, though, the reader is introduced to Captain Charles Hunter, who is the protagonist throughout the remainder of the book. The reader is then taken on a roller coaster ride as he/she follows the exploits of Hunter and his crew as they attempt to invade a Spanish fort, capture a Spanish galleon, and exact revenge.
It isn't until the reader nears the end of the book that it becomes apparent that the book was published posthumously. Several of the events near the end seem a bit rushed, and many of the conflicts reach an abrupt resolution. Fans of Crichton's scientific thrillers might not feel at home with this novel, but readers will be able to recognize and appreciate his writing style. Even if they're not usually fans of Crichton, historical fiction fans may find Pirate Latitudes to be a good read.
All said, if you find the hardcover in a bargain bin or run across a good deal on a paperback, it's worth a read.