Bernard of Clairvaux (1090-1153), who wrote this short book, was a Cistercian abbot and a prime mover in the reforming of this Order. In this, perhaps the most famous of his works, he explains that the way in which we should love God is to love him without measure. He then goes on to explain what the different degrees of this love are and which we encounter successively as we make progression in the spiritual way.