The Pilgrimage Road to Santiago by David Gitlitz and Linda Kay Davidson — A thorough account of the Camino routes through northern Spain, including the Aragonese path that passes through Jaca and the western Pyrenean valleys. More history than walking manual, it gives context to the Romanesque churches scattered across this landscape, including the one at Siresa just up the valley.
Aragonese Pyrenees by Robin Walker — A walking guide that doubles as a portrait of the region's culture and landscape. Walker writes about the valleys — Hecho, Ansó, Ordesa — with evident affection, and the background chapters on Aragonese language and village life are worth reading before you arrive.
Spain by Jan Morris — Morris's essay on Aragon, though a small portion of this large book, captures the character of the region's mountain communities with more precision than most dedicated guides. The sense of a people apart — self-contained, traditional, not much interested in tourism — reads recognizably true in Hecho.