‘A vision of innocence was not always the same as an innocent vision,’ remarks Robert Douglas-Fairhurst. He is referring to Alice’s discovery in Wonderland that ‘ “I say what I mean” is not the same as “I mean what I say”.’ Douglas-Fairhurst is a subtle expert in doubleness. His new book tells the story of Lewis Carroll, who was also an Oxford mathematician called Charles Dodgson, and Alice Liddell, whom Dodgson photographed naked when she was seven, who married and became Mrs Hargreaves though she liked to use the title Lady Hargreaves, to which she was not entitled.