Isaiah Berlin's celebrated radio lectures on six formative anti-liberal thinkers were delivered on the BBC's Third Programme in 1952. They are published here for the first time, fifty years on. Freedom and its Betrayal is one of Isaiah Berlin's earliest and most convincing expositions of his views on human freedom and the history of ideas, views which later found expression in such famous works as 'Two Concepts of Liberty', and were at the heart of his lifelong work on the Enlightenment and its critics. In his lucid examinations of sometimes difficult ideas Berlin demonstrates that a balanced understanding and a resilient defence of human liberty depend on learning both from the errors of freedom's alleged defenders and from the dark insights of its avowed antagonists. This book throws light on the early development of Berlin's ideas, and supplements his already published writings with fuller treatments of Helvetius, Rousseau, Fichte, Hegel and Saint-Simon, with the ultra-conservative traditionalist Maistre bringing up the rear. Freedom and its Betrayal shows Berlin at his liveliest and most torrentially spontaneous, testifying to his talents as a teacher of rare brilliance and impact. Listeners tuned in expectantly each week to the broadcasts and found themselves mesmerised by Berlin's astonishingly fluent extempore style. A leading historian of ideas, who was then a schoolboy, records that the lectures 'excited me so much that I sat, for every talk, on the floor beside the wireless, taking notes'. This excitement is at last recreated here for all to share.

以赛亚·伯林(1909—1997)　英国哲学家和政治思想史家,20世纪最著名的自由主义知识分子之一。出生于俄国里加的一个犹太人家庭,1920年随父母前往英国。1928年进入牛津大学攻读文学和哲学,1932年获选全灵学院研究员,并在新学院任哲学讲师,其间与艾耶尔、奥斯汀等参与了普通语言哲学的运动。二战期间,先后在纽约、华盛顿和莫斯科担任外交职务。1946年重回牛津教授哲学课程,并把研究方向转向思想史。1957年成为牛津大学社会与政治理论教授,并获封爵士。1966年至1975年担任牛津大学沃尔森学院院长。主要著作有《自由四论》（1969，后扩充为《自由论》）、《俄国思想家》(1978)、《反潮流》(1979)、《个人印象》(1980)、《扭曲的人性之材》（1990）、《现实感》(1996)、《浪漫主义的根源》（1999）、《启蒙的三个批评者》（2000）、《苏联的心灵》（2004）等。