La Forja describes the author's childhood and youth in Madrid prior to 1914 and his early schooling in Escuelas Pías in Lavapiés. During these years his mother worked as a laundress of military clothes, by the river Manzanares. The novel describes Barea's early ambitions of becoming an engineer and his frustration with a unequal social system that forces him to terminate his education and work in various jobs such as courier, shop attendant and bank employee.