I'm a big fan of the Osprey series, but the books on World War I aviation written by Norman Franks are disappointing. His books on the Nieuport and Albatros Aces, vol. 1 are especially weak. He certainly knows the bare facts about the planes, various units, and piliots like Albert Ball on the "micro" level, but he provides little context, or developmental overview, from a "macro" perspective. For instance, in the Nieuport book, he basically provides a static descriptive overview of each squadron and key piliots, which, although informative, needs to be balanced with an evolution of the Nieuport series from the Nieuport 10 and 11 to the Nieuport 17 and later models.
I would have liked to have seen a chapter on the Nieuport 11 during the "Fokker Scourge" and Battle of Verdun, delineating how and when it was deployed, number of planes, squadrons, key piliots, and how it fared aginst the Fokker Eindecker. I would have liked to have seen a similar approach to the Nieuport 16 and 17 during the Battles of Somme (both French and British units) and "Bloody April" in 1917, comparing the late Nieuport models against the Albatros DIII.
Such shortcomings are apparent in the Albatros Aces, vol. 1 as well. Perhaps the weaknesses of Frank's book prompted the need for a second volume by Greg vanWyndgarden, a far better writer who knows how to map out the larger contours and circumstances of German World War I aviation.