While RIPTIDE is a fictional tale of suspense, terror, and mystery, it is also based on research into such eclectic subjects as buried treasure, high-seas piracy, 17th century espionage and cryptology, forensic anthropology, as well as the latest high-tech tools of today's treasure hunters. Some of these are listed below.

--MORE THAN TWO CENTURIES AGO, a teenage boy exploring an island off the coast of Nova Scotia discovered a mysterious pit. When diggers excavated it, they discovered a flat stone 90 feet down, incised with a coded message. In lifting the stone, they apparently sprang a booby trap which caused the pit to flood with seawater. Ever since, explorers and investors, believing that the pit contained treasure, have tried to plumb its depths. But all attempts to date have failed, due to an ingenious system of secret traps and tunnels that keep the pit flooded. In 1988, Douglas Preston journeyed to the site, known as Oak Island, and spent several weeks on the treasure hunt. He subsequently wrote about the mystery for Smithsonian magazine, in what became the most popular article in the magazine's history. This and other fabulous accounts of hidden treasure were the initial inspirations for RIPTIDE.

--ONE OF THESE  ACCOUNTS was of the bizarre Victorio Peak treasure. In a mountain peak in New Mexico, deep in a warren of shafts, an estimated $2 billion dollar treasure is believed to be hidden. The Victorio Peak treasure is believed to have been assembled by Apache Indians from gold and ecclesiastical treasure stolen from the Spanish, Mexican, and Americans who traded along the Camino Real. For centuries, the Indians placed all their stolen gold at the bottom of a complicated series of caverns in the mountain in an attempt to create a "power spot"–knowing how much Europeans craved gold, the Apaches believed the metal might be the source of their military power. All attempts to gain the treasure have failed, leading some to speculate that the Victorio Peak might be cursed.

--THE PICTURE PAINTED in RIPTIDE of 17th century piracy is accurate. The pirate captain, Edward Ockham, who buried the treasure in RIPTIDE, is modeled on various real pirates, including:

Henry Every, who seized such spectacular treasure in the Red Sea in 1695 that one writer wrote that he "was likely to be the Founder of a new Monarchy." In one of his raids he captured, ravished, fell in love with and then married the daughter of the Great Mogul of India.

The educated gentleman and incomparable seaman, Bartholomew Roberts, who became the most successful pirate of the early 18th century simply "for the Love of Novelty and Change."

Edward Teach (Blackbeard), who commanded four ships with a crew totalling more than 400. He was infamous for his random cruelty and sadism; he once forced a captive Portugese to eat his own ears. When he went into battle, he covered his hat and enormous beard with lit sulphur-dipped splinters; the smoking, burning appearance of his head struck terror in his enemies.

Captain Edward Low, "a ferocious brute of unequalled cruelty" who once decapitated 53 Spanish captives with his own hand, but always spared married men because he missed his wife.

--THE ASTONISHING SIZE of the RIPTIDE treasure, big as it is, is not beyond the bounds of accuracy. After twenty years of salvage efforts, $350 million dollars worth of gold and silver was recently brought up from a single Spanish treasure galleon, the Atocha. The amount of treasure carried in the Spanish Flota de Plata,the 17th-century Plate Fleet, was staggering--the value of each ship's cargo might exceed half a billion dollars, perhaps half of it "off the books." A Dutch privateer accidentally sank ships with $11 billion worth of treasure when it tried to capture the Plate Fleet in a Cuban harbor in 1611. In 1721, the pirate John Taylor made the single biggest haul in pirate history when he captured a Portugese East Indiaman carrying the Count of Ericeira. The Count was carrying the world's largest diamond fortune, along with gold and silks. Each of Taylor's several hundred crew members got 42 big diamonds plus about half a million in gold. (In the drawing of lots one drunken pirate got a single, egg-sized diamond instead of 42 smaller ones: in a rage he bashed the diamond to pieces in a mortar and boasted that the got a lot more than 42 diamonds out of it.) A great deal of pirate treasure is still lost: experts estimate, for example, that Cocos Island, a favorite pirate hangout, still has $2 billion or more in treasure buried on it.

--ONE OF THE KEY ELEMENTS in RIPTIDE is the treasure hunters' attempt to decipher the coded secret of the Water Pit, written in the margins of an old treatise on architecture. Here the authors did extensive research on 17th century cryptology and code-breaking. The RIPTIDE code was written in "white ink"--invisible ink--which was one of George Washington's favorite methods to send secret dispatches. It was additionally encoded using a sophisticated encryption technique known as a polyalphabetic cipher. It requires a supercomputer in RIPTIDE to break the 17th century code.

--IN RIPTIDE, A MASS GRAVE of pirates is discovered on Ragged Island, in which bodies had simply been thrown into a hole and covered up. They seemed to have died of a mysterious, scurvy-like disease. The forensic anthropology in RIPTIDE used to identify the disease is accurate. Indeed, archeologists today can extract antibodies from old bone to show what disease the person died from, and by analyzing mitochrondrial DNA they can also trace blood kinship. For example, Oxford University scientists proved that a 9,000 year old skeleton found in a cave in England was found to be a direct ancestory of the local high-school history teacher--the longest blood kinship tie ever established.

--THE SCOTTISH DESIGNER of RIPTIDE'S Water Pit, William Macallan, is based in part on a 17th century Englishman named John Wallis. Wallis was England's greatest mathematician before Newton, a member of Britain's secret "Black Chamber," and a pioneer in the art of cryptanalysis, or code-breaking. Wallis, among other things, largely invented the concept of infinity. He was also an astonishingly gifted athlete who, it was said, could fling a coin so high that it rang off the vault of Salisbury Cathedral.

--THE AMAZING TECHNOLOGY used by the treasure hunters in RIPTIDE is also accurate, some of it based on recently declassified material. Robert Ballard, the discoverer of the Titanic, said recently that "with our powerful new technologies, everything lost in the sea over the past three thousand years will probably be recovered in the next five decades."