Caá Porã : El Espiritu de la Yerba Mate is a book about yerba mate written by Pau Navajas. It is a beautifully produced 464 page book  and brings the reader on a fascinating and exciting journey in time from the sacred origins of yerba mate to its place in modern Argentina. This is by far the best book available on the subject of yerba mate. Unfortunately it is only available in Spanish.