Lady Audley's Secret has been called "the most sensationally successful of all the sensational novels". The success of the book, along with Mary Elizabeth Braddon's other bestseller, Aurora Floyd, established the author as the main rival of the master of the sensational novel, Wilkie Collins. A protest against the passive, insipid 19th-century heroine, Lady Audley was described by one critic of the time as "high-strung, full of passion, purpose, and movement." Her crime (the secret of the title) is shown to threaten the apparently respectable middle-class world of Victorian England. The story centres on "accidental bigamy" which was in literary fashion in the early 1860s. The plot was summarised by literary critic Elaine Showalter (1982): "Braddon's bigamous heroine deserts her child, pushes husband number one down a well, thinks about poisoning husband number two and sets fire to a hotel in which her other male acquaintances are residing".
Elements of the novel mirror themes of the real-life Constance Kent case of June 1860 which gripped the nation for years. The follow-up novel (Aurora Floyd) appeared in 1863. There have been three silent film adaptations, one UK television version in 2000, and three minor stage adaptations.