Sir Morgan Crofton fought in the Boer War and joined the 2nd Life Guards at 34 years old as a cavalry office.
His diary charts his experiences on the front-line at Ypres from late October 1914 to the centenary of Waterloo in June 1915.
Crofton describes a battlefield a world away from what he and any of his comrades had experienced before - one of staying still in trenches, being pounded by artillery and the terrifying new power of machine guns.
He describes the bewildering pace of technological change as new weapons, such as gas and hand grenades entered the fray.
His often acerbic commentary offers a fascinating glimpse into the mindset of the regular officer class and his outspoken scepticism informs our understanding of a lost generation of professional soldiers.