KG 40 was the only long range maritime unit of the Luftwaffe. V Gruppe was the only long range fighter Gruppe within the unit. That alone makes the study of their operations an interesting topic.
As part of the Battle of the Atlantic, U-Boats transiting the Bay of Biscay became pray of RAF bombers. As a response measure, KG 40 activated a heavy fighter unit (Junkers 88 C-6) to intercept the bombers. As a response the RAF deployed the Beaufighter and later, Mosquitos into the bay. The Luftwaffe counter the move by deploying single engine Fw-190 fitted with long range tanks (from 8/JG2), but eventually, the sheer number of the Allied aircraft established air superiority over the bay.
The book has the following chapters