Biblical and Practical Approaches to Spiritual Formation by Kenneth Boa
This is one of the best books I have ever read on spiritual formation. It covers twelve different facets of Christian spirituality. Topics covered include (but are not limited to) falling in love with God, cultivating an eternal (versus temporal) perspective, grasping our true identity in Christ, and warfare spirituality. While the book was designed for use as a seminary text, it is very readable for all of the rest of us! I found many profound insights in this book that really did change the way I thought about certain issues.