This is a major contribution to the field of artistic photography and art history, and frankly, I am not sure what the previous reviewer was looking at or for when giving this award-winning set one out of five stars (it was rated "outstanding art publication of the year" by the Art Libraries Society of North America in 2002).
Greenough's 2-volume set is a standout in numerous ways. For starters, it is the first retrospective work that has attempted to establish some kind of chronological order to Stieglitz's photographs (many of his major works were never dated previously). Why is this important? Stieglitz was extremely influential not only as an artist but as a technician, introducing new photo cropping and printing methods at a time when photography was just starting out as a field of study. Without dates for his photographs, it had previously been impossible to determine for certain whether Stieglitz was employing (or improving upon) techniques that were already out there, or if he was forging ahead into unknown territory.
The scholarship undertaken here is impressive: in addition to the dating of all the material, Greenough provides copious notes about the images, including invaluable information about the reproduction process. There is a detalied appendix, bibliography, index, and concordances, as well as information of other Stieglitz photographs in other collections.
Apart from the scholarship, however, what makes this set standout is the quality and quantity of the images. There are over 1600 photographs in this set, and only about a third of them had ever been reproduced before. Many of the images here are print variants that Stieglitz produced from the same negative, showing how he experimented with printing (using carbon, platinum, gelatin silver, and palladium among other materials) as well as cropping/orientating/mounting of his prints. These images give us a more complete picture Stieglitz's thought processes in terms of his art, his experimental nature, and the methods he employed in presenting his vision to the world.