David Cordingly's Under a Black Flag is, as of this writing, the definitive work about a piratical life at sea. Many other books reference Cordingly and rightly so. He is extremely knowledgeable and his research is excellent. His style is conversational, though, so the academia doesn't get in the way. If you haven't read a book about pirates, this is a great place to start.
The Pirate Coast by Richard Zacks, which is now in paperback, is the fascinating story of America's first war on foreign soil. Held in Tripoli by the Algerian Dey, the crew of USS Philadelphia had little hope of rescue. President Jefferson wasn't going to be pushed around, however, and he sent an elite force of US Marines led by William Eaton to rescue the sailors and potentially overthrow the Algerine government. It's a rousing tale and one that was going to be a movie before 9/11 made this perceived "anti-Islam" moment in history too hot to touch. Read the book and find out why that's a bucket of bilge water.
Next we have The Pirates Laffite. Guess which of these offerings is Pauline's favorite? How did you know? William C. Davis, one of our foremost American historians and a Southern gentleman to boot, brings us the true and untempered story of Jean and Pierre Laffite. Davis is a master storyteller and, though his research is so exhaustive it makes me sleepy, this book is a page turner. Don't believe anything anyone who hasn't read and absorbed this book ever tells you about the Laffites and their ilk. They don't know what they're talking about. Period.
And, on the distaff side, there is Joan Druett's She Captains. Druett, much like Cordingly, is an expert on the history of seafaring and she brings all her knowledge to bare in this wonderfully written book. From ancient history to the modern day, Druett follows in the wake of women at sea. And there have been a lot of them, believe me.
There are my suggestions for the curious privateer in your life. Or maybe it's time to reward yourself after all that shopping and wrapping. Winter is always a wonderful time to curl up with a good read. Enjoy!