Published in 1968, this book seemed remarkably contemporary. The author's writing is verbose but highly readable and fast-paced. While it pretends to be a study of the lives of three early Celtic abbots, it is more properly a study of early Celtic expressions of Christianity using three abbots as structure points, Brendan as monastic pilgrim/adventurer, Columba as monastic exile/church father/builder, and Columbanus as monastic missioner. Much scholarly work has been made since this book came out that adds clarity and depth to much of the material, but I'd recommend this book to anyone interested in the origins of Celtic Church history or hagiography. It's a great historical study and has a strong pastoral emphasis in its informational content.