Young enthusiasts for the life of prayer cannot be too frequently reminded of the danger of applying directly to their own persons the doctrines they read about. As they grow older they often become so self-conscious or introspective that they cannot read the lives of saints or descriptions of mystic states without discovering parallels in their own interior lives. This is a weakness not confined to spiritual matters for we remember the hero of Three Men in a Boat who began reading a medical handbook and soon decided that he had the symptoms of all the diseases therein described except ‘housemaid's knee’. This is typical of those who read spiritual or physical medicine. It is necessary to repeat the warning against this form of introspection before beginning to discuss in detail the more passive forms of prayer and the higher states of the spiritual life.