It is a challenge to write a biography of a man who did little more than read and think, whose myopia turned to blindness in middle age, who was an auto-didact whose only real job was as a librarian, and who lived with his mother and her housekeeper in a poky Buenos Aires flat until she died at 99, when he was 75. Shortly before that, he wrote gloomily: “My father's library has been the chief event in my life...the truth is that I have never emerged from it.”