After withdrawing from his industrial engineering studies, José Caballero (Huelva, 1913 – Madrid 1991) decided to dedicate his life to art. Through Daniel Vázquez Díaz he came into contact with Cubism. In Madrid Caballero studied at the Real Academia de Bellas Artes de San Fernando [Royal Academy of Fine Arts of San Fernando] and attended the Residencia de Estudiantes [Student Residence]. His friendship with Federico García Lorca and other members of the Generation of 1927 brought him to Surrealism. He produced sets for the itinerant university theater group La Barraca. With a basis in realist figuration and precise draftsmanship, Caballero mixed dreamlike subjects, forms, and figures in a collage-like manner creating works reminiscent of those Salvador Dalí made following his paranoiac-critical method.

After the Spanish Civil War he temporarily ceased painting. In the early 1950s his work evolved from Expressionism with a figurative basis to informal abstraction. He successfully participated in the VII Salón de los Once [VII Salon of the Eleven] and at the XXV Venice Biennale, and was the subject of an individual exhibition in Madrid at the Galería Clan. From the 1960s his work combined material and graphic elements revolving around two main themes: walls and the death of the bull.