Archive Materials of Mieczysław Wallis are in the collection of Combined Libraries of Philosophy and Sociology Faculties of the University of Warsaw, the Institute of Philosophy and Sociology of the Polish Academy of Science and the Polish Philosophical Society. There are two files devoted to Henryk Elzenberg. They contain a rich historical material, not published before and not known to many people. It is a valuable source of knowledge in the field of the history of Polish philosophy. Wallis’s notes provide (...) a lot of unique informations both on Elzenberg’s private life and also his activity in the scientific community. Furthermore, they present his philosophical concepts, as well as his motions of life and adversities he had to cope with. M. Wallis’s memoirs are an unusual record of the friendship and scientific co-operation of the two scholars that lasted for a few decades. Wallis’s work creates also an intellectual testimony of the epoch, in which they both lived and worked. (shrink)