'Life is not worth living unless one can be indiscreet to intimate friends, ' wrote Isaiah Berlin to a correspondent. Flourishing inaugurates a keenly awaited edition of Berlin's letters that might well adopt this remark as an epigraph. Berlin's life was enormously worth living, both for himself and for us; and fortunately he said a great deal to his friends on paper as well as in person. The indiscretions, thought engaging, are of course only part of the story. Berlin is one of the towering intellectual figures of the twentieth century, and the focus of growing interest and discussion. Above all, he is one of the best modern exponents of the disappearing art of letter-writing. When this volume opens Berlin is eighteen, a pupil at St Paul's School in London. He becomes an undergraduate at Oxford, then a Fellow of All Souls, where he writes his celebrated biography of Karl Marx. When that is complete he moves to New College to teach philosophy, and after the outbreak of the Second World War sails to America in somewhat mysterious circumstances with Guy Burgess. He stays in the USA, working for the British Government (apart from visits home and his famous trip to the Soviet Union in 1945-6) until April 1946, when he returns to Oxford, and the volume closes. Berlin's letters are marvellously accessible, and as entertaining as a novel. During the two decades covered here we see his personality and career growing and blooming. In America he writes a regular telegram to his anxious parents, often saying just 'Flourishing'; the word is entirely apt, not only for his wartime experience, but for the whole of his early life, vividly displayed in this book in all its multi-faceted delightfulness.