George VI's broadcast to the nation on the outbreak of war in September 1939 - which formed the climax of the Oscar-winning film 'The King's Speech' - was the product of years of hard work with Lionel Logue, his iconoclastic Australian-born speech therapist.
But their relationship did not end there. In the years that followed, Logue was to play an even more important role at the monarch's side.
Mark Logue, co-author of 'The King's Speech' and 'The King's War', and grandson of Lionel Logue, follows this relationship through the dark days of Dunkirk and the drama of D-Day to victory in 1945.
Drawing on exclusive material from the Logue Archive - the collection of diaries, letters and other documents left by Lionel and his feisty wife, Myrtle - Mark provides a fascinating portrait of two men and their respective families as they together faced up to the greatest challenge in Britain's history.
There will be a book signing with the author after the event.