[Professor Jakub Karol Parnas: 140th birth anniversary].

In 2024, it will be 140 years since the birth of Jan Karol Parnas, one of the most outstanding biochemists and one of the most outstanding Polish scientists of the first half of the 20th century. The article presents a synthetic biography of Prof. Parnas, his influence on the organization of scientific life in interwar Poland, and presents his students and collaborators who created the so-called "The School of Parnassus". It shows how this figure still influences the thinking of Polish biochemists about their Society and the attitude towards biochemical communities abroad, especially in Ukraine, which owes as much to Prof. Parnas as Poland does.