Sir Isaiah Berlin dreaded the physical act of writing, so he paced rooms dictating into tape recorders and to exhausted secretaries, producing some of the most influential political philosophy of the twentieth century. This episode traces his path from a wealthy timber family in Riga, through a childhood memory of a Petrograd mob lynching a sniper during the 1917 revolution, to his family's escape to Britain in 1921 and his rapid rise at Oxford, where he became the first unconverted Jew to win a prize fellowship at All Souls.

We follow his wartime diplomatic dispatches read by Churchill, his all-night meeting with the poet Anna Akhmatova in Leningrad and the repercussions it brought her, and then unpack his major ideas: the Hedgehog and the Fox (originally a joke), the distinction between negative and positive liberty from his 1958 lecture, ...