To the world, he was Dr. Sacks, the brilliant neurologist behind bestselling books like Musicophilia and The Man Who Mistook His Wife for a Hat. To professor Susan Barry, he became Dear Oliver—her mentor, friend, and confidant over the course of their unlikely, engrossing ten-year correspondence. It begins with a letter that Sue almost doesn't send. Dear Dr. Sacks . . . You asked me if I could imagine what the world would look like when viewed with two eyes. Sue’s unheard-of case history—as a “stereoblind” patient who acquired 3D vision in adulthood—so fascinates Dr. Sacks that he immediately asks to visit her. As “Stereo Sue,” she becomes the subject of one of his indelible New Yorker pieces—and, as a fellow neuroscientist, his sounding board for every kind of intellectual inquiry. Their shared passions—from classical music to cuttlefish, brain plasticity to bioluminescent plankton—spark a friendship that buoys both of them through life’s crests and falls: as Sue becomes an author in her own right, as she supports her father in his decline, and as Oliver becomes a patient himself—battling cancer that, in a painful twist, robs him of his own vision. Dr. Sacks’s letters to Sue offer his devoted readers an unprecedented glimpse of the man himself—from his legendary compassion and insight to his love of the periodic table (which he kept in his wallet). Throughout Dear Oliver , we are reminded that true friends help each other see the world a little differently.