I think Robert Harris is one of the great entertainers of the last twenty years. He can write a thriller like no one else, and his take on historical fiction is consistently challenging (although I have to say I struggled with Pompeii which seemed to be largely about Roman sewage technology). Enigma is my favourite for two reasons. Firstly, and obviously, it’s incredibly exciting, one of the few books that genuinely did keep me up all night. The second reason is more personal. My mother worked at Bletchley Park as a young woman during the war. She didn’t talk about her experiences for years, and I remember how shocked she was when books started to come out about the codebreakers in the 80s, as they’d all been sworn to eternal secrecy. I lent her Enigma and she read it with a certain amount of trepidation, but she was blown away by how accurate it was, right down to the freezing temperatures in the huts where they worked. She remembers Alan Turing, by the way, as a very shy eccentric man who wore odd socks.