The renowned German reference work The Handbuch der Zoologie/Handbook of Zoology was founded in the 1920's by Professor Willi Kükenthal in Berlin and treated the complete animal kingdom from single cell organisms to mammals in eight thematic volumes: Volume I Protozoa, Porifera, Colenteratea, Mesozoa (1925); Volume II Worms (1933/34); Volume III Arthropoda ex. Insecta (1927/1932); Volume IV Arthopoda: Insecta; Volume V Solenogastres, Mollusca, Echinoderma (1925); Volume VI Pisces / Amphibia (1930); Volume VII Reptilia / Aves (1931); Volume VIII Mammalia. The Volumes Insecta (Eds. N.P. Kristensen, R.G. Beutel) and Mammalia (Eds. M.S. Fischer, H. Schliemann) continued publication into the present with the most recent contributions in English language. Covering nearly 100 years of zoological research, the Handbook of Zoology represents a vast store of knowledge. But with the speed of scientific discovery in the past decades, a new edition of the Handbook in a new form is required. Beginning in 2010 the Handbook of Zoology was restructured and offered additionally as a database (Zoology Online) which can be easily searched and rapidly updated. The eight thematic volumes were replaced with smaller and more flexible groupings that reflect the current state of phylogenetic knowledge. Faster publication times through online-prepublication make the Handbook of Zoology highly attractive to both authors and users.