Arts & Crafts
The American Craftsman style (along with a wide variety of related but conceptually distinct European design movements) was developed out of the British Arts and Crafts movement, which began as early as the 1860s.
The British movement was reacting against the Industrial Revolution's perceived devaluation of the individual worker and resulting degradation of the dignity of human labor. The movement emphasized handwork over mass production, with the problem that expensive materials and costly skilled labor restricted acquisition of Arts and Crafts productions to a wealthy clientele, often ironically derided as "champagne socialists".
While the American movement also reacted against the eclectic Victorian "over-decorated" aesthetic, the Arts and Crafts style's American arrival coincided with the decline of the Victorian era. The American Arts and Crafts movement shared the British movement's reform philosophy, encouraging originality, simplicity of form, local natural materials, and the visibility of handicraft, but distinguished itself, particularly in the Craftsman Bungalow style, with a goal of ennobling modest homes for a rapidly expanding American middle class.