The true story of loss of His Majesty's Submarine Thetis is still shrouded in mystery, even now, some seventy-five years after her sinking. On 1st June 1939, HMS Thetis sank in Liverpool Bay on her maiden dive, with the loss of ninety-nine lives; the worst peacetime submarine tragedy ever to be suffered by the Royal Navy. As soon as the impending disaster was reported, a massive rescue operation was mounted by the Royal Navy, but, following a catalogue of mis-understandings, political posturing, 'red tape' and sheer incompetence, the operation ended in abysmal failure, with only four of the crew being rescued. There were many on-going recriminations and a number of legal battles, following the Royal Navy's private inquiry, and the subsequent public inquiry. Even after such forensic examination, nobody was held to be culpable for the disaster. As a result of media coverage at the time, a number of conspiracy theories were spawned, some gaining more credence than others, in light of the inconclusive findings of the official reports. In Thetis: Submarine Disaster, David Paul, having studied the events surrounding the tragedy of HMS Thetis for many years, examines the issues which led to the disaster, and draws some conclusions.