The Secret Kingdom is a 1938 novel by the British writer Walter Greenwood.

[1] It portrays the working-class socialist Byron family, and particularly the eldest daughter Paula who tries to establish an independent identity after finding working a parlour maid.

She encounters Bert Treville in nearby Manchester and the two begin a courtship.

After his death due to heavy drinking, she brings up her son Lance as a single-mother, throwing her effort into her talented child she is vindicated when he emerges as a talented concert pianist - performing on national radio in the final scene.

[2] Greenwood had in the 1940s had written a screenplay based on the story, but it remained unproduced.