This book is a fairly dense but well written exploration of how Zen might help Catholics "to realize more fully their own spiritual inheritance." Graham's take on Zen in relation to Catholicism is theologically astute and experientially grounded.Graham, who was a Benedictine monk, notes that he is not inviting readers "to embark on a daring theological adventure" (the book received an ecclesiastical imprimatur). Rather, he is inviting readers "to look into [their] own nature and that of the Church" and to consider Graham's suggestion that, at their existential depths, Zen and Catholicism share the same basic message.This book was first published in 1963, but I think it's still one of the best books relating Buddhism and Christianity.Also recommended: Ruben Habito's "Living Zen, Loving God."