Unamuno worked in all major genres: the essay, the novel, poetry, and theater, and, as a modernist, contributed greatly to dissolving the boundaries between genres. There is some debate as to whether Unamuno was in fact a member of the Generation of '98, an "ex post facto" literary group of Spanish intellectuals and philosophers that was the creation of José Martínez Ruiz (Azorín) — a group that includes, besides Azorín, Antonio Machado, Ramón Pérez de Ayala, Pío Baroja, Ramón del Valle-Inclán, Ramiro de Maeztu, and Ángel Ganivet, among others.