The book is the result of many years of viewing the literature and fieldwork by the author team and their ongoing commitment to map out the nomenclature of this genus. During this process, the authors even discovered some new plants. More than 300 high-quality colour photos showing the various cacti and their habitats as well as distribution cards and illustrations explaining the morphological details complement the text. Written in an easy-to-follow style and with a chapter on cultivation conditions, the work will not only be an invaluable reference manual for taxonomists and horticulturalists but also for hobbyists and plant collectors.