On a brutally cold night in February 1864, all seemed calm off the coast of Charleston, South Carolina. But beneath the placid surface of the sea, a Confederate submarine named the H. L. Hunley was about to attack the USS Housatonic, the Union Navy's largest warship. The sub plunged a 135-pound torpedo into the Houstonic's stern, sinking it within three minutes, and becoming the first submarine to sink a ship in battle. Lieutenant George Dixon and his crew signaled their victory to their Rebel compatriots on Sullivan's Island and steamed toward shore and a heroes' welcome. Sadly, their triumph was short-lived: For reasons that remain mysterious, the H. L. Hunley abruptly disappeared.

But not, it turns out, forever. Though treasure-hunters had searched for the sub since the Civil War, it remained undisturbed for 136 years. Aided with newly-developed technologies, a team of divers bankrolled by novelist Clive Cussler found the Hunley in 1995.

As described by the authors of The H. L. Hunley, the sub’s discovery and subsequent recovery have revealed a veritable treasure trove of human-interest anecdotes and solutions to decades-old mysteries.