Maybe we should get Doc Ford a silver snorkel.Caribbean Rim is Florida author Randy Wayne White’s 25th novel about Marion "Doc" Ford, marine biologist and freelance investigator-spy, and that’s a significant milestone in the realm of crime fiction series.White’s books are consistent national bestsellers, winning fans with a potent mix of vivid Florida settings (based on White’s longtime residence on Pine Island and Sanibel), fascinating dives into the state’s history and prehistory, plenty of hold-your-breath action and a cast of intriguing characters, led by no-nonsense, formidable Ford and his polar-opposite sidekick, the mystic sailor-philosopher Tomlinson.Ford’s usual territorial waters are those around his home on Sanibel, but this book finds him in the Bahamas. He’s just coming off a week of gratifying isolation on an uninhabited island there, "the skin-on-bone reality of a tent, zero electronics, miles of beach to run, the indifference of saltwater, tide, wind."He packs up his recently acquired Maule seaplane and heads for Andros Town to look for a "man he wanted to find but had no reason to hurt, let alone kill."Someone on the island, he discovered, possibly did."The man in question is Leonard Nickleby, an anthropology professor turned bureaucrat. That doesn’t sound like the kind of guy who’d inspire assassination, and in his former life the slight, balding, scholarly Nickleby wouldn’t have.But that was before Lydia.Lydia Johnson was one of his most promising students before she inexplicably dropped out of college. She was mousy and shy, but they had a strange connection. When Nickleby runs into her a few years later at the Ocala National Forest, he’s become an employee of the Florida Division of Historical Resources, and she’s fresh off a stint working for Benthic Exploration, a treasure salvage outfit whose founder went to prison.Their meeting turns into an affair, which turns into a scheme to leave behind their pasts (including his bad marriage) and salvage some treasure of their own to finance an island life.That scheme includes purloining a logbook from Carl Fitzpatrick, a friend of Ford’s, "an aging treasure hunter who had invested forty years of travel, hard work, and research in the notes the book contained." The lovers hope it will lead them to the treasure from one of the countless sunken ships scattered like beads around the Bahamas, a Spanish ship that went down with a storied cargo of gold. On his friend’s behalf, Ford hopes he finds them first, but he might not be the only one on the hunt.Lydia and Leonard — or Lady Anne and León, as they’re now styling themselves — have shed the skins of their old lives. As one Bahamian tells Ford, Nickleby reminds her of "a nervous little dog who’d been caged and coming here was his first taste of freedom. Barking for attention and running wild."Ford’s efforts to track down the pair are complicated by an array of unpleasant characters, among them a dive guide with a nasty temper named Hubert Purcell, an ex-military kickboxer known as Aztec and Efren Donner, a Hollywood producer escaping the stink of a sex scandal — not to mention some of the most massive oceangoing white-tip sharks he has ever seen (and Ford has seen a lot of sharks).He also discovers that his trickster uncle, Tucker Gatrell (from The Man Who Invented Florida, the third Ford book and maybe still my favorite), might have fathered some offspring in the Bahamas.Tomlinson shows up as well, of course, to befriend an old fisherman-preacher named Josiah Bodden who knows about a lot more than fish, and to undertake the rescue of a young woman in peril.The Bahamas are awash in pirate history — Lydia borrows her "Lady Anne" alias from a real 17th century buccaneer named Anne Dieu-le-Veut — and, it seems, the pirates are not all historical. The key to the treasure everyone is hunting might lie on a strange island called White Torch Key, whose few inhabitants, called the Marl People, shun outsiders. Catching up with Lydia and Leonard and solving the mystery of the missing gold will call for all of Ford’s considerable resources. But a letter that Tomlinson finally delivers to him might just change his life.Fans of White’s books will welcome this 25th entry in the series. If you haven’t read any of them yet, you might want to get acquainted with Doc Ford — his namesake restaurant will soon have a location in St. Petersburg as part of the new Pier project.White’s book signing Wednesday will be at the St. Petersburg Museum of History, practically next door to the site of the upcoming Doc Ford’s Rum Bar and Grille. It’s a fine opportunity to welcome him to the neighborhood.Contact Colette Bancroft at [email protected] or (727) 893-8435. Follow @colettemb.