There are only a handful of books covering waterfalls in New York State, and the others are quite regional. This book stands out due to its near comprehensive coverage, and mostly good directions for getting to each. All the waterfalls worth visiting are covered. The regional books do have a few additional sites, but I generally find these to be smaller or on private property. This is due to their author's somewhat more intimate knowledge of their respective areas.
I was very pleased with the introductory chapter on safety. Waterfalls can be lethal locations without proper attention and equipment. And I have talked to people who have been 'ledged'.
The photographs are extremely useful, and there are tips on location for many sites. Some photographs also carry tips on exposure when the author has had probelms at specific locations. There is no chapter dedicated to photography, unfortunately, as most of the tips are generalizable to all... and waterfalls are an exceptionally difficult photographic subject.
I checked the content for several dozen locations that I have visited frquently. The text driving directions seem generally good. Some of the location maps are not accurate, but not so seriously bad that you would get lost (if you can follow a trail, you will have no problems). In addition at some locations, some of the available waterfalls are not mentioned. At Lick Brook Falls (Sweedler Preserve) the 'trail' to the base of the tallest waterfall is not mentioned. Of course, it's not a marked trail, but one which will be well rewarded for your effort. The GPS locations seem to be accurate.
None of the books devoted to NYS waterfalls is perfect. I gave a 5 star rating for its comprehensive coverage. This is the one I would prefer to carry in the car with me, along with DeLorme's NYS Gazetteer or Topo USA on a laptop.