This straightforward and lucid book examines the use of criminal law to enforce moral standards, particularly in the area of sexual morality. This topic has attracted the interest of jurists and legal philosophers since the publication of the Woolfenden Commission report in 1957. This book is a polemic with the British legal scholars James Fitzjames Stephen and Patrick Devlin, who criticized John Stuart Mill's thesis that "the only purpose for which force can be lawfully applied to any member of a civilized society against his will, is to prevent harm to others.” Hart examines in it the most important problems of freedom, tolerance, the right to privacy and sexual morality, the grounds and limits of state intervention in the lives of citizens. The book served as a great stimulus for further discussion of this issue and the formation of modern concepts of the “principle of harm”, legal paternalism and legal moralism.