Cistercians are the reform order of Benedictine monks dating back to the High Middle Ages. As ingenious technical designers, they laid down the basis for intensive agriculture. Their ideal of piety was far ahead of the mendicant orders and made the Benedictine order attractive again in the time of the Investiture Controversy.

The book covers the history of the Cistercians from their oundation by Robert of Molesme and Bernard of Clairvaux, through their cultural, scientific and social function in the Middle Ages to the present day, although its focal point - the importance of the order - was in the Middle Ages.