WHEN M. JOHN FAYHEE first arrived in New Mexico's rugged Gila Country, he was a naive 20-year-old who didn't know a javelina from an enchilada. Much has changed in the intervening half century.In this meandering memoir, Fayhee, with his loyal dog Casey at his side, takes us through the heart of the Gila - once the stomping ground of Geronimo and Billy the Kid and home to the world's first legally designated Wilderness Area - as he endeavors to hike every day for a solid year through some of the country's most remote and challenging terrain. "A Long Tangent" explores the process of going from wide-eyed young man tocrotchety old fart as he comes to terms with his mortality, with the fact that "There are many more trail miles behind me than there are ahead."More than that, though. This is the story of the bond between a man and his canine companion as it evolves through deep canyons, across bone-dry mesas in ninety-five degree heat and toward the cactus-covered mountains that rise above the desert lands of southwest New Mexico.Along the way, Fayhee reflects upon rattlesnakes, hiking sticks, bears, exploding rocks, mystery mountains, disorientation, poorly worded religious texts, lost pets, marriage, the relationship between hikers and their vehicles, and a past that slips ever further into the rearview mirror.