This is the history of a pre-war TF division, the 1st London Division. It had the unhappy experience of being broken up right at the beginning of the war to provide reinforcements elsewhere. By the beginning of 1915 the division had ceased to exist, but in January 1916 it was reconstituted in France and numbered '56th'. Its first major engagement was the unsuccessful diversionary attack at Gommecourt on 1 July 1916 which resulted in 4,749 casualties. The division remained on the Somme till October and in the following year fought in the 1917 Arras offensive and again at Cambrai. In the German March 1918 offensive the 56th formed the right flank of First Army NE of Arras where, alongside 4th Division, it faced seven German divisions in the 'Mars' offensive; the German advance here was checked. By the end of the war the division had suffered 34,809 casualties. This account is by an author with a reputation as a writer of regimental and divisional histories, and his experience as a regimental and staff officer in the war show clearly. There is an excellent appendix providing details on order of battle - commanders, staff and units - and the changes, with dates.