Jacinto de la Serna, Manual de ministros de indios

A handbook by the parish priest of the Sagrario of Mexico City, written to help other priests recognise and stamp out Nahua ritual practice. To make it usable he printed the thing he meant to destroy: healers' testimony in their own account of it, the herbs they used, the incantations word for word. The same pages record the death sentences, the forced searches and the imprisonments that produced the testimony.