Here's another Aubrey/Maturin with a strange title. The Surgeon's Mate begins just a day or so after the book The Fortune of War ends. Sailing triumphantly, if only as passengers, into Halifax on board the Shannon, which has just defeated an American ship, Aubrey, Maturin and even Diana are looked at as heroes. In Halifax, Diana finds out she's pregnant with Johnson's child and Aubrey has an affair with a silly Miss Smith. The trio has an exciting trip home, chased by American privateers after Maturin. Then Steven goes to a conference in Paris, taking Diana there to live until she has her baby. Steven then has to come back to England for a mission to the Baltic with Jack as the captain of the Ariel.
It is an exciting, fast paced book that has a good bit of character development as well. One of my favorites so far. a 6!
BTW, Jo Walton explained what the title means in her review over on Tor.com. She is reviewing the whole series; spoilers abound!