The Walker Brothers--John, Scott, and Gary--were one of the biggest pop groups of the 1960s. Gifted with stunning voices and drop-dead gorgeous looks, their appeal was irresistible. Massive hits such as "Make It Easy on Yourself" and "The Sun Ain't Gonna Shine Anymore" have become evergreen classics. During the time of the British Invasion, the Walker Brothers were one of the few American acts to matter overseas. Yet within three years, the group...