Full colour facsimile reprint of the original First World War, War Office war diary of the Headquarters, Branches and Services Royal Army Medical Corps Assistant Director Medical Services, 4th Division, covering August 1914 to June 1916 across 924 pages. It names 58 places across 98 dated entries.

Alongside the daily entries the volume carries six reports, narratives and plans, five Operation Orders, five appendices and six maps. Among the papers are: R.A. operation orders O' Callaghan O.C. RAMC 4th Div; R.A.M.C operation order by Col D.M.O Callaghan O.C. R.A.M.C. 4 Div; Operation orders by Colonel D.M.O' Callaghan A.M.S A.D.M.S. 4th Division.

The diary opens at Southampton on 22 August 1914. 1914 is the most travelled year, 59 places against 13 in the next busiest, and is spent at Nieppe, La Carriere L' Eveque, Carriere L'Eveque, Jossigny and Venizel. 1915 is spent at Acheux, Nieppe, Trois Tours, Vlamertinghe and St Sixte. 1916 at Bavincourt, Acheux, Ribeaucourt, Couin and Warluzel. It closes at Bertrancourt on 30 June 1916. Acheux is where it spent longest, 203 days across eight separate stays, including a single unbroken stay of 34.

Trench and battlefield features named in the diary include Chateau Maucreux, Chateau Tartarel, Chateau Chenoine and Chateau Trois Tours.

In 1914 it is also recorded at Havre, Busigny, Inchy, Biastre, Viesly, Haucourt, Vendhuille, Roizel, Hancourt and Voyennes. In 1915 it is also recorded at Chateau Trois Tours and Watou. In 1916 it is also recorded at Lucheux and Vauchelles.