A historian of law, bibliographer, journalist and director of the Jagiellonian University, born in 1869 in Krakow. He died in Sachsenhausen in 1939. Charles Estreicher‘s son. He studied law in Krakow at the Jagiellonian University, Berlin and Vienna. Professor and three-time dean and vice-rector of the Faculty of Law. He continued his father’s work on “Polish Bibliography”, extending the meaning of its content and scope. He wrote dissertations, articles on literary, theatrical, social and even political topics. He has published in “Pamiętnik Literacki”, “Rocznik Krakowski” and others. Co-founder of the Society of Krakow History and Monuments Lovers. It is worth emphasizing that he was the co-organizer of the museum Matejko House. He died in a concentration camp after being arrested by the Gestapo. General Sikorski’s government posthumously awarded him with the Cross of Valor.