Cussler's most adult, least comic-strip-y entry yet in the Dirk Pitt sea sagas. Gone is the outlandish plotting of Treasure (1988), when Dirk found Cleopatra's barge in Texas, and of Sahara (199), which unearthed Lincoln's body in a Confederate sub--buried in the desert sands. Now, in his 11th outing, Dirk Pitt and his National Underwater and Marine Agency (NUMA) fight villainous megalomaniac Arthur Dorsett, head of Dorsett Consolidated Mining, which holds the world's wealthiest diamond-mine empire. Pitt and his team must fight as well Dorsett's three daughters, the coldly beauteous Amazonian Boudicca, whose giant strength dwarfs Dirk's; the elegant but heartless Deirdre; and the star-crossed zoologist Maeve, whose bastard twins are held captive by grandfather Arthur so that Maeve will infiltrate NUMA and report on its investigation of his holdings--even though Dirk recently saved Maeve and Deirdre's lives in the Antarctic. First, however, Cussler takes us back to 1856 and a typhoon-battered British clipper ship, the Gladiator, that sinks in uncharted seas off Australia; only eight survive, including Jess Dorsett "the highwayman," a dandyish-looking convict, who discovers raw diamonds when stranded on an uninhabited island. From this arises the Dorsett empire, bent on undermining the world market in diamonds by dumping a colossal backlog of stones and colored gems into its vast chain of jewelry stores and, with one blow, toppling De Beers and all rivals. Worse, Arthur Dorsett excavates by high-energy-pulsed ultrasound, and when ultrasound from all four of his island mines (one on Gladiator Island, near New Zealand, another by Easter Island, the last two in the North Pacific Ocean) happen to converge, a killer shock wave destroys all marine and human life for 30 kilometers around, and now threatens over a million people in Hawaii--unless Dirk Pitt's aging body can hold it back. Tireless mechanical nomenclature, but furious storytelling.