Restless is an espionage novel written by William Boyd, published in 2006. It won the Costa Prize for fiction.The novel depicts the tale of a young woman who discovers that her mother was recruited as a spy during World War II. Eva, a young Russian woman, is recruited after her brother's death to work for the British secret service. During this time she falls for her mentor and boss, Lucas Romer. But all is not as it seems as Romer is working as a double agent which ultimately leads to the attempted murder of Eva, alongside the deaths of other agents.

The tale is interlinked with the story of Eva's daughter in the 1970s and how she comes to terms with the discovery of her mother's secret life. The setting of the novel is in London, Oxford, Scotland, Europe, and the United States.