The Cactus family is an almost entirely New World group of unique plants. Within the Neotropics there are only a few geographical centres of cactus diversity. The third most important of these is Eastern Brazil. Phytogeographically isolated from other cacti habitats by 'hostile' environments, this region boasts a high percentage of endemic taxa, making it a discrete area of study and of great importance for conservation. This landmark publication includes 77 full page colour plates and 51 colour maps.