Munthe’s book is a well-argued contribution to the PP debate, putting neglected justificatory and methodological questions at the forefront. His many discussions of alternative accounts as well as his drawing out the consequences of his own suggestion in practical cases give the reader a thorough, holistic sense of what justification of PP amounts to. /..../ Munthe’s main case, his argumentation for the requirement of precaution as a moral norm, is convincing and puts a strong pressure on too narrow alternative suggestions on how it should be perceived and justified, and he launches a plausible defence of its practical usability.