The book tells about the life and work of the outstanding Polish writer and teacher Janusz Korczak, who died along with his students in the gas chamber of a fascist concentration camp.Ya. Korczak left little information about himself. The material for the book was mainly based on numerous letters and memoirs of his contemporaries, primarily the writer Igor Neverly, who worked as Janusz Korczak’s personal secretary and spoke in detail about the relationships between children and teachers in Korczak’s “Orphanage”. Against the backdrop of the dramatic events of the 20th century, the story reveals the personality of the remarkable humanist - author of famous books about children “King Matt the First”, “Kaitus the Wizard”, “The Bankruptcy of Little Jack”, which reflected the hopes and disappointments of J. Korczak himself in the implementation of social justice.