In the summer of 1998, Walter Kirn -- then a young novelist struggling with fatherhood and a dissolving marriage -- set out on a peculiar, fateful errand: to personally deliver a crippled hunting dog from an animal shelter in Montana to the New York apartment of one Clark Rockefeller, a secretive young banker and art collector. Thus began a fifteen-year relationship that drew Kirn deep into the fun-house world of an outlandish, eccentric son of privilege...