Abigail Dean was born in Manchester, and grew up in the Peak District. She graduated from Cambridge with a Double First in English. Formerly a Waterstones bookseller, she spent five years as a lawyer in London, and took summer 2018 off to work on her debut novel, Girl A, ahead of her thirtieth birthday. Girl A was an instant bestseller and has been sold in 36 territories. Day One is her second book.