Tommy: The British Soldier on the Western Front 1914-1918 by Richard Holmes. It goes into the life and experiences of the ordinary British soldiers in France and Belgium. Holmes does a bit of myth busting such as the non-existent phrase 'Lions led by Donkeys'. He also points out that more generals were killed in one battle (Loos) than in the entire 2nd World War. He makes the point also that the bitterness felt towards the war was coloured by experiences after the war when returning to peacetime. He also notes that criticism of generals like Haig began after they had died and could not answer critics. It does not cover the battles in any depth but what life was like for the Tommy. It also reveals why British soldiers were called Tommy. It came from an example in one of the army books where a Thomas Atkins of the Dragoon is used as its subject.
It also makes the point that the Somme was necessary in order not only to relieve pressure on the French at Verdun but because the Italians and Russians were on the offensive as well.