The lichen flora of the Nordic countries has been regarded as one of the best known in the world, containg about 2000 species. the lichenological research of the region has been going on continuously since the days of Eric Acharius (1757-1819), the " father of lichenology". It has, however, been a painful and awkward fact that there is no mordern flora treatment of the region, the last attempt being that of Th. M. Fries in the 1870-ies, a work (Lichenographia scandinavica) that was left unfinished. A number of Nordic lichenologists have united forces to produce such a work, and we can now proudly present the third volume, comprising the cyanolichens, including "the small black ones" which have not been critically surveyed in our region since 1885. We hope that the next volumes will be publiched at shorter intervals than this one which took five years to complete.