"Tracking: Signs of Man, Signs of Hope" by David Diaz, 2005, about 220 pages. Mostly combat tracking. Some on pressure release-type tracking and interpretation, some sign and aging also covered. Interesting identification of the finest trackers in the world as indigenous Malays, Dyak/Iban of Brunei, Nigrito aborigines of the Philippines, San Man of Botswana, and Montagnards of Laos, Cambodia, and Viet Nam. Worth a read.