Jan J.T. Srzednicki & Z. Stachniak 
Lesniewski’s Systems Protothetic [PDF ebook] 

Between the two world wars, Stanislaw Lesniewski (1886-1939), created the famous and important system of foundations of mathematics that comprises three deductive theories: Protothetic, Ontology, and Mereology. His research started in 1914 with studies on the general theory of sets (later named `Mereology’). Ontology followed between 1919 and 1921, and was the next step towards an integrated system. In order to combine these two systematically he constructed Protothetic – the system of `first principles’. Together they amount to what Z. Jordan called `… most thorough, original, and philosophically significant attempt to provide a logically secure foundation for the whole of mathematics’. The volume collects many of the most significant commentaries on, and contributions to, Protothetic. A Protothetic Bibliography is included.