Facundo: Or, Civilization and Barbarism by Domingo Faustino Sarmiento: published in the 19th century, a highly critical view of Argentine caudillos Quiroga, Rosas, & others
Argentine Caudillo: Juan Manuel de Rosas by John Lynch: a far more balanced assessment than Sarmiento's
Imagining Argentina by Laurence Thornton: a very readable (though grim) novel about the generals & the desaparecidos
I've donated Caudillo & Imagining to the Estancia library.
Now reading Wade Davis's One River, a superb account of ethnobotanists & hangers-on (including Richard Evans Schultes, Tim Plowman, Andrew Weil, Wade Davis, William Burroughs) combing South America & Mexico for hallucinogenic plants. A blog post on Schultes here. Wiki article here.