The bible for succulentophiles,
This review is from: Encyclopaedia of ISI Plants, 1958-1996 (Paperback)
During the years that I was actively collecting cacti and succulent plants, I desired to obtain specimens with provenance. Unless one knows where a plant comes from, or how it came to you, it seems to me that half of its value is lost. Much can be learned about a given specimen from this provenance and this enhances the collecting and growing experience.
This Encyclopedia of ISI Plants lists every single plant that was offered by the International Succulent Introductions scheme from 1958 at its inception until 1996. Some of these plants are quite famous. Each entry has an ISI number attached to it and it was under this number that the specimen was originally known and released. This listing gives both cacti and general succulent introductions, and they are kept separate from each other in their own sections.
I valued this compendium immensely during the years of my active work in succulents. Highly recommended!