In the first part of the book, the authors discuss analytical, psychological, sociological as well as mixed forms of legal positivism. From the Hart-Dworkin debate, two new doctrinal trends have emerged which both build on Hart and strive to defend him against Dworkin’s criticism: “Exclusive Positivism” on the one hand and – depending on the author – “Soft Positivism” or “Inclusive Positivism” on the other hand. The differences between the various positivist theories stem from the different definitions of the term “law” used by the various legal writers. In the second part of the book, the authors therefore analyze the question whether – by using scientific methods – one of the definitions of the term “law” can be proved to be true. The question must be answered in the negative, because the positivist definitions of the term “law” are neither empirical “statements” describing a certain given object nor analytic definitions conveying a certain meaning of the term “law”. Rather, they are synthetic-semantic stipulations stating a certain meaning of the term “law”. Stipulations can be neither true nor false but must be evaluated by examining their usefulness. The reason why the positivists developed so many different theories thus becomes obvious: All these theories are based on a pre-scientific premise but not on a scientific finding which can be proved to be true. In the third part, the authors develop a certain interpretation of legal philosophical thinking (which they call “axiomatic theory of law”). According to this interpretation, systems of legal philosophy differ sharply from empirical theories: The latter may be put to the test of being true or false while this is not possible for systems of legal philosophy: They are to be assessed by the consequences in which they result, i.e. by the merits and demerits which are the result of any such theory. Finally, the authors examine the well-known objection that legal positivism furthered the “perversion of the law” in the Third Reich (so-called “Hitler Argument”). This objection is demonstrably false from a legal historical and jurisprudential perspective.