This book was originally published in Polish (Ksie?garnia Akademicka, Krako´w 2009) under the title Prawnicze poje?cie obowia?zywania prawa stanowionego. Krytyka niepozytywistycznej koncepcji prawa. I decided to introduce minor changes and additions to the Polish text in order to make the content comprehensible for a non-Polish readership. Additionally, I removed those parts that were addressed exclusively to Polish readers. I would like to thank S?awomira Wronkowska, Robert Alexy, Tomasz Gizbert- Studnicki, Ulfrid Neumann, Lech Morawski and Marek Zirk-Sadowski for their support and assistance in obtaining the finance for the translation of this book into English and for its subsequent publication by Springer-Verlag. I express my gratitude to Alexander von Humboldt-Stiftung for a scholarship— which made it possible for me to analyse German nonpositivism—as well as for the financial support given for the publication of the English version of the book. I also thank the Polish State Committee for Scientific Research (KBN) for a research grant connected with developing the postpositivist concept of the validity of statutory law and the Foundation for Polish Science (FNP), which granted a subsidy to cover the costs of translating the book. Last but not least, I greatly appreciate the help and accurate editorial guidance provided by Anke Seyfried, who supervised the publication of this book by Springer-Verlag.