This textbook, written in 1947 by a well-known Russian specialist in the history of philosophy, logic and literary criticism V.F. Asmus (1894-1975), was at one time the first work on formal logic, published in the USSR after a long period of nihilistic attitude to this scientific direction. This book largely laid the foundation not only for the publication of scientific and pedagogical literature on logic, but also, without exaggeration, for the return of formal logic to the Russian education system. In his textbook V.F. Asmus preserves and develops the best traditions of the Russian logical school, relying on the ideas of M.I. Karinsky and S.I. Povarnin. First published more than sixty years ago, this book has not lost its significance to the present and will be useful both for university students studying logic and for everyone who wants to get acquainted with the basics of traditional logic on their own.