Naejangsa (Temple)
Photo by Peter Garnham used under a Creative Commons license.

David A. Mason, Spirit of the Mountains: Korea’s San-Shin and Traditions of Mountain-Worship (Hollym International Corp., 1999).
Writing about Korea in Salon‘s Literary Guide to the World, James Card says:

. . . Mason spent the last 20 years putting in trail miles and doing fieldwork devoted to his research of mountain shamanism. His book . . . offers a revelatory look at how this native religion is quietly practiced at individual shrines and Buddhist temples across the country. San-shin, a mythical persona, is depicted as a wizened white-bearded sage who inhabits the mountain valleys, creating sacred spots of power and spirituality. In the first sentence of the book he writes, “Right at this moment, as you read this page, no matter what time or season it is, mountains are being worshipped in Korea.” Mason dissects the iconography of tigers, pine trees and ginseng, and the book doubles as a travel guide to the shrines. Many guidebooks will tell you a thousands facts about a famous Buddhist temple, yet Mason’s book teaches you to explore behind the temple and follow a jagged path in the woods that leads to a weathered stone altar dedicated to the spirit of the mountains.

Mason’s web site has a whole lot of interesting stuff on it, including biographical information. This article about Mason seems to have run first in The Korea Times. Here’s a review by John Synott. And Brendon Carr recommends it. Here’s a lengthy discussion at The Well with Mason about the book. Mason prepared this annotated map of sacred sites in Korea. And here are more writings by Mason on the web site of the Korea Branch of the Royal Asiatic Society.

Buy it at Amazon.com (but n.b. — Amazon appears to think that the book’s author is named “Weatherhill”).