Written to give lay Catholics a better understanding of the Eucharist, this book is recognized as a modern spiritual classic. In remarkably clear and straightforward language, it takes the reader step-by-step into the deepest mysteries of the Eucharist—a religiously exhilarating journey into the heart of the Christian faith.

"Profound insights… I recommend this excellent book to all Catholics who desire a better understanding of the Mass."
—Father Kenneth Baker, S.J., Editor, Homiletic & Pastoral Review

"This is a beautiful book-one of the great treasures of the Catholic renewal of the last century."
- Christoph Cardinal Schönborn

" One could wish most earnestly that every Catholic-and every Protestant for that matter-would read Abbot Vonier's book. Both the mystery and the richness of the Eucharist are here: but the book is splendidly readable-no small achievement."
- Thomas Howard

"Stephen Langton, the 13th-century Archbishop of Canterbury, famously said, 'If you wish to learn, five things are necessary: purity of life, simplicity of heart, an attentive mind, a humble disposition, and a gentle spirit.' Abbot Vonier's book on the Eucharist exemplifies the beauty and radiance of all five of these virtues. Not since St. Thomas Aquinas's treatment of this sacrament in the Tertia Pars of his Summa Theologiae has there been a more lucid and serene presentation of the Catholic understanding of the Eucharist than this book. It should be required reading in every course in sacramental theology in every Catholic seminary and college in the nation."
- Edward T. Oakes, S.J.

"A Key to the Doctrine of the Eucharist is one of the few classics in Catholic theology composed in English... This book, remarkable for its balance, depth, and accessibility, should never be out of print."
- Avery Cardinal Dulles