If there's one book I should buy as a paperback this summer, it would be...

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If you had to recommend one book to buy as a paperback to read on the beach or by the pool this summer, which would you recommend?

Madeleine Miller and Pat Barker's Greek mythology books also great and 'House of Glass' by Hadley Freeman (non-fiction) as mentioned upthread was superb. I picked it up on a whim and ended up reading it for a few hours!