The Cruel Sea is a 1951 novel by Nicholas Monsarrat. It follows the lives of a group of Royal Navy sailors fighting the Battle of the Atlantic during the Second World War. It contains seven chapters, each describing a year during the war. The novel, based on the author's experience of serving in corvettes and frigates in the North Atlantic in the Second World War, gives a matter-of-fact but moving portrayal of ordinary men learning to fight and survive in a violent, exhausting battle against the elements and a ruthless enemy.