The story of Trident and the Vanguard class of submarines, the successor to Polaris. Following on from his Polaris: The History of the UK's Submarine Force, Keith Hall turns his attention to the next phase of the story: Trident. After the Polaris subs were decommissioned in the mid-1990s, the four Vanguard class submarines carried on the UK's Continuous At Sea Deterrent policy (CASD). Armed with American Trident missiles, these submarines are expected to run until at least 2028 as the UK's only nuclear weapons platforms. This new study describes the history of the UK seaborne nuclear deterrent; the purchase and arguments surrounding the American Trident missile system; the development of HM Naval Clyde to accommodate these new submarines and their crews; and what life is like aboard the submarines themselves. AUTHOR: Keith Hall was a Health Physics Specialist at HM Naval Base Clyde. He served in the Royal Navy for over 30 years, both on nuclear submarines and in shore positions. He has previously written Rosneath and Garleloch, HMS Defiance: Plymouth's Submarine Base, HMS Dolphin: Gosport's Submarine Base, Submariners' Tales from the Deep, Clyde Submarine Base and Polaris: The History of the UK's Submarine Force for The History Press. He lives in Helensburgh.