Piranesi is a fantasy novel by English author Susanna Clarke, published by Bloomsbury Publishing in 2020. It is Clarke's second novel, following her debut Jonathan Strange & Mr Norrell (2004), published sixteen years earlier. The novel is set in a parallel universe made up of an infinite number of halls and vestibules, which triggers a gradual loss of memory and identity in newcomers. The story is told through the research notes of the eponymous narrator, who reconstructs the story of his own arrival as he explores this world. Piranesi won the 2021 Women's Prize for Fiction.

Susanna Mary Clarke is an English author known for her debut novel Jonathan Strange & Mr Norrell (2004), a Hugo Award-winning alternative history. Clarke began Jonathan Strange in 1993 and worked on it during her spare time. For the next decade, she published short stories from the Strange universe, but it was not until 2003 that Bloomsbury bought her manuscript and began work on its publication. The novel became a best-seller.