Yes, Kevin, you're right about the cover. I bought a copy at Telford. and the cover artwork shows a DH 9 jin the process of bringing down a Fokker D.VII which is falling away streaming smoke. (I posted a photo in the latest acquisition thread.)
I think this is a really important and relatively neglected area, but feel that Osprey have been rather cautious and unambitious in devoting just one volume to it. At the very least there was scope for a volume on such German aces and another on their Allied equivalents. Still, a very interesting read.
Best wishes
Nigel