By Carthusian Monks of the fourteenth to seventeenth centuries. I have just received this totally amazing prayer book via Amazon. What a treasure in today's world when orthodox, authentic prayers can be hard to find. It is large print, hard or soft back (I chose hard) with foreword by Cardinal Robert Sarah. Full of devotions to the sacred heart and our Blessed Mother from 400-700 years ago and totally relevant to today, including a week of daily exercises to the Sacred Heart. What a treasure to own, not only an addition to my library but a book I can use every day to inform my prayer life. I could not be more delighted, please excuse my gushing I'm just overcome with joy.