Twenty metres below water, the oceanographer Fran ois Sarano came face to face with a five-and-a-half metre great white shark. Seduced by the gentle elegance of this majestic creature, Sarano experienced a profound sense of affinity with her as they swam side by side, shoulder to shoulder, eye to eye, cutting a single figure through the ocean depths. It was an experience which made him realize the depth of our ignorance of the lives of sharks,...