Stanislaw Lesniewski (1886-1939) was one of the leading Polish logicians
and founders of the Warsaw School of Logic whose membership included,
beside himself, Jan Lukasiewicz, Tadeusz Kotarbinski, Alfred Tarski, and
many others. In his lifetime LeSniewski published only a few hundred
pages. He produced many important results in many areas of mathematics;
these stood in various relations to each other, and to materials
produced by others, and, in time, created more and more editorial
problems. Very many were left unpublished at the time of his death. Then
in 1944 in the fire of Warsaw the whole of this material was burned and
lost -a considerable loss since a great deal of what is important could
have been reconstructed from these notes. The present publication aims
at presenting unique Lesniewski's materials from alternative sources
comprising lecture notes taken during some of Lesniewski's lectures and
seminars delivered at the University of Warsaw be- tween the two world
wars. The editors are aware of the limitations of student notes which
cannot compensate for the loss of the original materials. However, they
are unique in reflecting Lesniewski's ideas as he himself presented
them. Already at the time of his death it was realized that these notes
would provide a unique access to Lesniewski's own thought as well as a
valuable record of some of the activities of the Warsaw School of Logic.