A unique contribution to the study of the UFOs, originally published over 30 years ago, this updated edition includes new photographs and illustrations, and an extensive Foreword by David Hatcher Childress discussing more recent Underwater UFOs -- now called USOs -- Unidentified Submersible Objects. In the last 30 years, new sightings have occurred and new information on old sightings has come forth through the Freedom of Information Acts in the USA, Britain and Australia. These curious incidents during official military manoeuvres raise many questions: Do the British and Americans have underwater military bases capable of launching UFOs? Could the ultimate docking stations for some of the UFOs seen constantly around the world be deep in our oceans? Could these still-operational underwater docking bases have been built in our distant past by extraterrestrials? Sanderson chronicles hundreds of curious unidentified underwater object incidents, many which emerge from the water to fly through the air, and draws some startling conclusions.