From the back cover:

The Boeing B-17 has come to epitomise the American war effort in Europe, the huge four-engined heavy day bomber taking the fight to Germany from the late summer of 1942 through to VE-Day. The primary operator of the Flying Fortress in Western Europe was the 'Mighty Eighth'. This volume, which is the first of two dealing exclusively with the 'Mighty Eighth', covers the 15 Bomb Groups of the First Air Division, each of which controlled four squadrons. The evolution of the force is traced through first-hand accounts of those individuals that took part in the action.