Martín Ramírez (January 30, 1895 – February 17, 1963) was a self-taught artist who spent most of his adult life institutionalized in California mental hospitals, diagnosed as a catatonic schizophrenic.

[9] At DeWitt, a visiting professor of psychology and art, Tarmo Pasto, came across Ramírez's work and began to save the large-scale works Ramírez made using available materials, including brown paper bags, scraps of examining-table paper, and book pages glued together with a paste made of potatoes and saliva.

[10] His works display an idiosyncratic iconography that reflect both Mexican folk traditions and twentieth-century modernization: images of Madonnas, horseback riders, and trains entering and exiting tunnels proliferate in the work, along with undulating fields of concentric lines that describe landscapes, tunnels, theatrical prosceniums, and decorative patterns.

In January 2007, the American Folk Art Museum in New York City opened "Martín Ramírez," the largest retrospective of the artist's work in the United States in more than 20 years.

In mediation, the Dunievitz and Ramírez families reached an amicable agreement in 2008, which includes the representation of this work by the Ricco/Maresca Gallery in New York City.

[14] In March 2015, "Untitled (Tunnel with Cars and Buses)" (1954), as well as four other designs, were reproduced as a stamp by the United States Postal Service.