"Engage the Enemy More Closely" was the signal flying from the HMS Victory's halyards at the Battle of Trafalgar, from 12.15 until it was shot away.
Engage the Enemy More Closely is also a book by Cornelli Barnett. Written in 1990, it describes the actions of the Royal Navy in the second world war. In the most recent Penguin Classic Military History edition, it comprises 1052 pages, and is divided into four parts. They are:
Part 1: Brittanica Lets the Trident Slip (1918-1940)
Stretching from the Battle of Jutland to the Dunkirk evacuation.
Part 2: Storm Force1940-1941
Telling in full about the Mediterranean Blue Water strategy and the Atlantic Grey Water strategy, as well as the Battle of Matapan and the sinking of HMS Prince of Wales and HMS Repulse.
Part 3: The Long Voyage Home1942-1945
Malta, 1942. Operation Husky. The desolate and dangerous Arctic convoys.
Part 4: Victory
In this final chapter, Barnett describes the victory in Europe and tries to draw conclusions, as well as describing the British post-war naval strategies.