This important book, written in somewhat baroque and not always clear English, provides a wealth of information for all those studying or working with Cyanoprokaryotes. That are the organisms usually known as Cyanobacteria or still just bluegreen algae. A modern book on identification, but only on the unicellular or colonial members, not on the important filamentous groups. Two parts will follow later. Although in the ‘Anschrift der Authoren’ it is indicated that Professor Anagnostidis has died, no further information is given about that sad event. The introduction is very important for users and reviewers. The editors printed in bold “Please, read this chapter” and they are right. Without reading this no-one would know that the book contains “a review of all Cyanoprokaryotic taxonomic units, registered and recognisable from European natural biotopes, including marine coasts.” And that “non-European species and species with vague taxonomic descriptions are listed under the appropriate genera.” The book was written for identification and standardisation of morphologically and ecologically distinguishable European Cyanoprokaryotes, that have been described from natural populations. The keys and taxonomic descriptions in the book permit identification of natural populations and some culture material; however, they are less suitable for identification of non-European specimens. Moreover, according to the authors, “identification of strains without previous knowledge of natural material needs to be studied with special care, because only a few Cyanoprokaryotes keep their typical form in culture.” The authors strongly dissuade the use of taxon names to include specimens or strains that deviate from features that are characteristic for “any higher taxon”. And they warn: “If the incorrect name is accepted, all the information about any given population or strain is a priori wrong.” And “Identification of any species is correct only if your material corresponds fully (in all characteristics, including ecology) with the description. The variability of species can be broader than described in the book, but you must be convinced of the taxonomic identity of your material.”