This edition of the Dictionary of Pseudonyms includes all the materials collected by I.F. Masanov in the period 1900-1945 by using a variety of printed as well as archival sources. The alias dictionary consists of two departments. In the first department (volumes 1-3), alphabetical indexes of pseudonyms are given (separately for the pseudonyms of the Russian, Latin and Greek alphabets, as well as astronyms and other signs). The second section of the dictionary (volume 4) will contain an alphabetical list of authors whose pseudonyms are disclosed in this edition.