By 1917, the year this War Office manual was issued, the machine gun had become king of the western front - its lethal rule bloodily proved on July 1st 1916. Based on the Vickers and Maxim guns - but also making reference of the US-made Lewis gun, the booklet covers the organisation of Machine Gun companies; the training and drill; fire direction; and the use of machine guns in actual battle conditions. It is illustrated by photographs showing correct and incorrect firing positions.