The history of the project that eventually led to the publication of the present handbook series was outlined in the preface to the Monocotyledons volume, published in the summer of 2001. A short summary of its history will therefore be sufficient: Handbooks devoted to succulent plants (including cacti) have a long-standing tradition. First treatments covering the family Cactaceae were already published in the 19th century, but the first handbook dealing with the so-called 'other succulents', authored by Hermann Jacobsen, was only published in 1954 - 1955, then called "Handbuch der sukkulenten Pflanzen". A revised and - larged English edition was published 1959 and was repeatedly reprinted subsequently. The success of this first handbook led to the publication of the more compact "Sukkulentenle- kon", again authored by Hermann Jacobsen, published 1970 in a German edition and 1975 in an English translation. Subsequent to Hermann Jacobsen's death in August 1978, Klaus Hesselbarth edited the revised German edition, published 1981. First ideas leading to the present "Illustrated Handbook" were developed prior to the 19- congress of the International Organization for Succulent Plant Study (IOS) in Zürich. Gustav Fischer Verlag Jena, publisher not only of Hermann Jacobsen's "Sukkulentenlexikon", but also of the equally reknowned "Kakteenlexikon" by Curt Backeberg, was interested to have new editions of these works prepared. The feeling amongst participants of an ad-hoc meeting during this congress was that the situation presented a unique occassion to produce a set of authoritative volumes embracing all succulent plants.