A fairy tale story by a famous Polish writer about a boy who, at the cost of difficult and sorrowful experiences, realized the joy of simple things that had previously seemed boring to him: living at home, loving his parents, making friends with his peers and possessing the greatest wealth in the world - a clear conscience. Janusz Korczak ( 1878–1942) is an outstanding Polish teacher, writer, doctor and public figure. The book was written in 1935 and, unfortunately, this is the last work of fiction written by Korczak. Like other works of art by Korczak, “Kaitus” introduces the reader to the complex world of child psychology and contains observations on the life of Poland in the 20s and 30s. XX century, reflects the rich experience of a doctor and teacher. Despite the fact that this is a book for children (teenagers to a greater extent), it is not so easy to read and will be interesting for adults too. It intertwines a fairy tale and questions regarding morality and morality. This book teaches rather than entertains.