spanish critic and philosopher miguel de unamuno comments of the book, "i never took "facundo" by sarmiento as a historical work, nor do i think it can be very valued in that regard. i always thought of it as a literary work, as a historical novel". however, "facundo" cannot be classified as a novel or a specific genre of literature. according to gonzález echevarría, the book is at once an "essay, biography, autobiography, novel, epic, memoir, confession, political pamphlet, diatribe, scientific treatise, [and] travelogue". sarmiento's style and his exploration of the life of facundo unify the three distinct parts of his work. even the first section, describing argentina's geography, follows this pattern, since sarmiento contends that facundo is a natural product of this environment.