Heraldry in the Catholic Church: Its Origin, Customs and Laws Hardcover – January 1, 1978

Another must have for the heraldic library.

Author Bruno Heim has left us with the definitive work on Catholic ecclesial heraldry. It's doubtful that a work like this will again be written. Heim's designs dominated this area for generations. His written explanations are most valuable for anyone working in heraldry today. This book is expensive, but I don't know anyplace else that you will get this depth of information on the subject.