This is one of what seems like many dozens of books on Cactus and it barely stands out as uinque in any way. It has nice illustrations of many of the species, as do many other books. It is in strict alphabetical order, which I like, instead of grouped by 'categories' of cacti as some more 'taxonomically' correct books are. There is a small paragraph describing each species of which there is a photo. And the book seems relatively current on genera, using the current names instead of the old ones I see in so many other books available. Amd many of the photos are of plants in habitat, which gives the viewer a lot more information about the plant than do photos of cacti in pots.
However, my primary complaint about this book, as with any other plant book calling itself an Encyclopedia, is that is far from inclusive, providing only a miniscule handfull of species of each genus, and leaving out several genera here and there. So, for identification purposes, unless you luck out and happen to have a plant that they just happened to put a photo in of, you will not find this a very useful book. Still, it is a nice 'coffee table' book, well photographed, and not too large to pick up and look at.