Prayer
This book is an excellent introduction to, and survey of, the practice and experience of prayer for Christians. Richard Foster draws from many different traditions and experiences and distills them into this very fine and accessible work. It's very practical, unpretentious and inspiring. Foster helps us examine the many facets of prayer grouped according to three intentions on personal transformation, intimacy with God and ministry to others. Among its 21 chapters you may find aspects of prayer that are very familiar to you (maybe you had never thought of them as prayer before) along with encouragement to focus and deepen your efforts in those areas. Other types of prayer may be completely foreign to you but offer an invitation to explore.
For those who want to take prayer more seriously this book is a very good place to begin. It is not an introduction in the sense of being superficial or shallow. It treats each aspect of prayer in enough depth to get the willing reader well on his or her way to a more effective and vital life of prayer. But it also shows us prayer as a vast, life long and life changing endeavor and points to the work of others who have explored the various disciplines of prayer more deeply. This books is essential reading.