This book describes how daily prayer can be used as a way of spiritual development. It is perhaps the first full and clear explanation of this process as seen from the Orthodox perspective, written during the last times of classical Russian monasticism. The second half of the book contains a selection of prayers by the early fathers of the church chosen to aid the reader who wants to put the ideas of this book into practice. There is also a three page biography of Theophan at the end of the book.
From the inside cover by Theophan:"Prayer is the elevation of the mind and heart to God in praise, in thanksgiving, and in petition for the spiritual and material goods we need. The Saviour commanded us to enter into our inner room, and there to pray to God the Father in secret. According to Saint Demetrius of Rostov, the inner room means the heart. Consequently, the commandment of the Lord obliges us to pray noetically to God in our heart. This commandment extends to all Christians. The Apostle Paul commands the same, saying that we must pray all the time in our nous."
"Paul commands mental or spiritual prayer for all Christians without exception. He also orders all Christians to pray unceasingly. To pray unceasingly is only possible in the heart. Therefore it is impossible to contest the fact that noetic prayer is compulsory for all Christians, and if it is obligatory, then it is also possible - God does not command the impossible."

A summary from Sermon Four, a life of prayer:
"I have now spoken to you about techniques of prayer three times:1. About the method of reciting prayers with attention,
2. About the method of ascending to God with mind and heart in accord,
3. And about the method of standing constantly in the presence of God with burning spirit.

In order that everyone can take part in the blessing of prayer to the measure of his capacity, the Lord has showed us different steps and different kinds of prayer. Because the work of prayer is a great labour, it is, as I said earlier, the proof of the life of spirit, as well as its food. Because of this, above all else, we should strive for perfection in prayer."