Ruth Haley Barton
A great person to read if you're wanting something more in your spiritual life but not sure where to start. Her books are personal and practical.
David G. Benner
As described by Inter Varsity Press, Benner is an author and psychologist whose primary passion is "helping people walk the human path in a deeply spiritual way and the spiritual path in a deeply human way."
Jan Johnson has written prolifically on spiritual formation. Her writings include articles and Bible studies as well as books.
One of the leading authors on spiritual formation in the protestant community, Willard seamlessly blends philosophy, theology and a strong love of Christ. His philosophical style will appeal to deep thinkers.