This book includes maps and descriptions of distribution and ecology of 376 species (336 maps) of most rare and threatened bryophytes on the territory of Eastern Europe. Mapping was made on 400 squares around 100 100 km on base geographical map system – Universal Transverse Mercator (UTM) with help of original computer programs. Distribution of еhe species on the territory of 6 biogeography regions and 12 subregions are showed. This atlas may be useful for preparing of new edition of European Red Book of Bryophytes, another bryological investigations and nature protection activity.