This unusual, pathbreaking book is a collaborative project of the In Flanders Fields Museum at Ypres, the Imperial War Museum in London, and the Royal Army Museum in Brussels. Besides hundreds of aerial photographs recovered from forgotten collections in several countries, it provides detailed maps, documents, overlays, and ground-level photos in a unique visual record of an important part of the Western Front during the First World War.

In The Great War Seen from the Air, Birger Stichelbaut (Ghent Univ.) and Piet Chielens (In Flanders Fields Museum) explain the rapid evolution of the new technique of aerial reconnaissance across a range of uses from artillery spotting to camouflage, operations planning, and military cartography. Again and again, they illustrate how to read war-relevant details of photographs that might appear to the untrained eye to show merely pastoral countryside, but for the networks of trenches and the bomb craters. Their book opens a genuinely fresh vein of material for researchers in an impressive array of "lost and forgotten aerial photographic collections" (340–43). Its provision of the GPS coordinates of specific features on individual photographs will aid both researchers and tourists more familiar with ground-level images of muddy, corpse-cluttered battlefields than with bird's-eye views of the "suffering of the countryside" in the Great War.

Many will agree with the assertion in the book's preface that aerial photos are "a more objective source than the many photographs taken on the ground, since they were, for example, not of Allied bodies but only those of the enemy; more objective than the best novels or war diaries refined by the filter of literary creation; more objective than trench maps, always of course drawn up without the knowledge of the enemy" (6). Yet, even granting this clinical objectivity, what precisely the images add to our sense of the war's "cultural landscape" is not so clear.

The book comprises two parts: first, a short, well written introduction to the evolution of aviation, cameras, and reconnaissance photography during World War I. And second, a systematic analysis of 129 case studies of photographs selected from a database of over twenty thousand images. The authors provide archeological, topographical, and human activity perspectives on the photos. They do not merely match contemporary images with the vestiges of scarred landscapes that stand today as the war's last witnesses. Oversize pages of photos and many transparent color overlays disclose new perspectives on the terrible trench warfare waged in Flanders Fields, giving us direct insights into how analysts of the day saw and used the information provided by airborne scouts.

The case studies are presented more or less chronologically—the first months of war, Second Ypres and the trenches, the British offensives of 1917, the German offensives and Allied breakout of 1918. They particularly concern the town and battlements of Ypres and include fascinating photos of postwar reconstruction well into the 1920s. They reveal the true scale of the trench systems on both sides, as well as the deep engagement of rear areas (hinterlands) that included fixed artillery positions, bunkers, barracks, fortified canals, railways, new roads, airfields, storage depots, hospitals, tank parks, port facilities, and bases for submarines, Zeppelins, and bombers.

Aerial photography did not emerge as a routine reconnaissance method before the Great War—Wilbur Wright took the first-ever photograph from an airplane only in 1909, over Italy. Instead, scouts initially made reports based on their sketches or mental notes of their observation flights. That changed rapidly beginning in September 1914, when a British lieutenant took photos near Antwerp, demonstrating that scout planes could provide accurate distant observation unequaled in the history of war. Once the trenches extended from the Alps to the North Sea coast, posing an impassible barrier to scout movement behind enemy lines, the advantages of planes over the ancient reliance on the eyes of cavalrymen or spies became obvious to all sides. Aircraft and cameras were now indispensable to artillerymen, mapmakers, and operations planners.

While the British began to develop aerial reconnaissance cameras before the war, the other belligerents had to scramble to exploit the new technologies. The problem of standardizing cameras was not overcome till 1915. An urgent reconnaissance arms race or "war of the lenses" added telephoto lenses, improved optics (a field dominated by Germany), and better mounting systems on longer-range aircraft. To the end of the war, Belgian, British, and American reconnaissance personnel relied on the French to produce superior lenses.

As the analysis of aerial photographs became more acute and professional, scout planes directed ever more accurate artillery fire on the enemy. But not until the end of 1916 did awareness of this threat lead to greater efforts to conceal potential targets from observation. In response, stereoscopic techniques were devised to improve the identification of structures, terrain elevations, and camouflaged sites.

The book gives many examples of the three main types of aerial photos used for intelligence purposes: vertical, oblique, and panoramic. Vertical shots (that is, taken directly downward from an overpassing aircraft) are the hardest to read. The authors enhance them by adding transparent colored overlays and short explanations. Oblique shots are far more distorted but easier for laypersons to read. Wartime analysts, however, found them ill-suited for "conversion into cartographic data .... Their chief importance is in helping to understand the terrain's topography and its military installations. The image they create is similar to that obtained by looking down from the top of a hill" (23). Panoramic photos provided infantry with a better sense of terrain in no-man's-land and any obstacles to attack or defense.

In the first months of the war, flyers simply held cameras over the side of their aircraft, taking oblique photos that tended to confirm visual observations on the ground. But as both technique and analysis improved, vertical shots taken by fixed automatic cameras came to dominate, meeting a rising demand for continually updated and detailed trench emplacement maps, at varying scales. By war's end, aerial reconnaissance had transformed military cartography: a single German camera could produce a stereoscopic record of 250 photos of a battlefield 2.4 by 60 kilometers in area during a single flight.

The book's unique "multi-layered landscapes" approach to the case studies makes them readily accessible to most readers, including historians. All three types of photos are used to identify the natural, historical, and military layers of each targeted landscape. Color-coded highlights on transparent overlays permit easy recognition of natural and built terrain features. The authors' concentration on Flanders reveals a striking disparity between the prewar topography of copses, hills, and rivers that shaped the initial disposition of the trenches and the same landscape as it was progressively destroyed, reshaped, or even obliterated by years of heavy fighting.

Each case study may stand on its own. Perhaps the most evocative set of images shows a German cemetery around a military hospital. The successive (mapped and marked) extensions of the cemetery as casualties rose feature narrower and less individualized grave spaces. In the third extension, we see graves closely packed in rows of fifteen and lacking crosses. A large final expansion lies vacant, awaiting future arrivals of yet more of Imperial Germany's dead sons.

The narrative lacks detail to match the hundreds of photographs; for instance, there is no mention of the Canadians at Third Ypres. But that is an understandable and forgivable shortcoming in a book that so forcefully clarifies how massive an endeavor the Great War really was, how thick with effort and labor and matériel and humanity. Every black-and-white photograph and colored and indexed overlay of even a limited slice of Flanders Fields presents awful and inspiring visual confirmation of the written record of the war in the trenches. We join those long-ago pilots flying over the war itself, cameras clicking away under the wings of open planes, recording and helping to form landscapes of suffering and death on a scale beyond imagining.