Tatiana and Krista Hogan are extraordinary little girls. Conjoined twins are a rarity, but those joined at the head, craniopagus twins, are the rarest of all — one in 2.5 million. But it is the structure of their brains that makes them unique in the world. They have the astonishing ability to see through each others’ eyes, feel what the other experiences, perhaps even know what the other is thinking. Inseparable follows the twins through a year in their lives and a landmark birthday — their tenth — surrounded by a loving family who insists on treating them as normal.