Geek Girl is a No.1 bestselling series, which has been translated into thirty languages and has sold 3.4 million copies since its publication in 2013. It won the Waterstones Teen prize for that year, as well as being short-listed for the Roald Dahl Funny Prize. It follows the journey of Harriet Manners, self-proclaimed geek, as she enters the world of fashion in an attempt to change her life - and herself.

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The TV adaptation (co-created and co-written by Holly) launched with Netflix, Nelvana and Ruby Rock Productions in 2024, and was a No.1 worldwide hit. 

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The book series consists of six main books, two novellas and a World Book Day short.

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