Cyanoprokaryotes are probably the oldest organisms with plant metabolism. However, their cell structure and type of asexual reproduction prove their eubacterial origin. They are able to colonize all possible biotopes, including very extreme environments (thermal springs up to 80 DegreesC, rocks in extremely hot or cold deserts in both the tropics and Antarctica, hypersaline lakes and marshes, biotopes in volcanic regions, and other harsh habitats).

This book was written for identification and standardization of known, morphologically and ecologically distinguishable European Cyanoprokaryotes that have been described from natural populations. In the introductory part only data important for identification practice are therefore included. At the end of this chapter we append a list of this basic literature, which comprises all the necessary detailed information. We have selected accurate drawings of described species.