Amos Walker is a fictional character in a series of books by sometime western author Loren D. Estleman. He is a private detective who lives on the Detroit-Hamtramck border and works in Detroit, Michigan. Like Estleman, who pecks out his books on a 1967 Olympia manual typewriter, Walker is wa-a-ay low-tech. At one point, the middle-aged P.I. turns on his cell phone and draws its antenna out with his teeth. (When was the last time you saw a cell phone with a retractable antenna?!)