‘Gentlemen prefer blondes,’ Anita Loos pronounced, ‘but gentlemen marry brunettes.’ Quite what they do with redheads she never revealed (and I’ve often wondered), but with Red: A Natural History of the Redhead, Jacky Colliss Harvey sets out to discover everything — what it takes to make a redhead, where in the world they come from and why they exist at all; whether redheads are actually different or just treated differently; how they got their reputation, what that reputation might be and whether they deserve it.