The famous O'Neill collections of Irish music, which preserved thousands of melodies, are named after the man who originated the collecting of the tunes and arranged for the publication of the tunebooks in the early 1900s, Francis O'Neill, then superintendant of the Chicago police force. However, another (no relation) O'Neill named James, a fiddle player born in Co. Down and also a Chicago policeman, had a most crucial role to play in the compilation of the collections, specifically as the one who would write down the tunes the two men hunted down, hence the title of the present book. Mac Aoidh, a fiddle player himself and previously the author of "Between the Jigs and the Reels - The Donegal Fiddle Tradition," has written a fascinating biography, one which will appeal especially to those interested in the origins of tunes and how they were shaped for publication. Understandably, this is as much a book about the circumstances in which the O'Neill collections were produced and what is known of that process. Mac Aoidh relied on his considerable knowledge of the early printed literature of Irish music, but also did some real detective work to create a compelling narrative.