The Society for the Diffusion of Useful Knowledge (SDUK) was an educational society established in 1826 that published a series of inexpensive books on scientific and technical subjects.

The goal of the SDUK, which has been characterized as "a Benthamite-oriented group",^[1] was to "improv[e] workers' efficiency and ad[d] to the nation's pool of inventors and engineers."^[2] In a letter to John Stuart Mill, Thomas Carlyle—famous for his criticisms of democracy, economics, and utilitarianism—derided the Society's "triumphant quackle-quackling intent only on sine and cosine."^[3]