Handbooks devoted to succulent plants (including cacti) have a long-standing tradition, and the demand for updated editions is a good indication of the high degree of interest that exists in this fascinating group of plants. While first handbooks devoted to the family Cactaceae were already published in the 19th cen- tury, the first handbook dealing with the so-called 'other' succulents was authored by Hermann Jacobsen and published in 1954 -1955, then called "Handbuch der sukkulenten Pflanzen." A re- vised and enlarged English edition was made available in 1959 and was repeatedly reprinted...