author
Drawn from the people who served in it, this book gives a close-up view of the 5th Battalion Highland Light Infantry in the First World War. It follows the unit from mobilization through hard campaigning, with the detail and immediacy of a regimental history written soon after the war.

by 5th Great Britain. Army. Highland Light Infantry. Battalion
F. L. Morrison is credited as the author of The Fifth Battalion Highland Light Infantry in the War 1914-1918, a history first published in 1921. Sources connected with the book identify him as Colonel F. L. Morrison, and the work itself is presented as a record of the battalion's service during the First World War.
The book traces the unit's story from its mobilization and training in Scotland to overseas service, including Gallipoli and other wartime campaigns. Contemporary and library-style records also describe the volume as a regimental history written for private circulation, which helps explain its practical, first-hand feel.
Reliable biographical information about Morrison apart from this book is limited in the sources I could confirm here. Based on those sources, the clearest picture is of a military author closely connected with the 5th Battalion Highland Light Infantry and committed to preserving its wartime memory.