This book has a good introduction, and tells the basics about the morphology, ecology and cultivation of Cactaceae. Most of the book contains large and excellent photos of several cacti species in cultivations. Each photo is followed by a scientific name (and cultivar name when necessary), and a very short description.
For a beginner on cacti cultivation, I found this book very good, showing me many new and suprising informations and great pictures. But many more hardcore cacti growers may find this book a bit shallow.