Augsburg Books has a series called “40 Day Journey with ____________.” The blank is a person. For example, “40 Day Journey with Parker Palmer.”
I may not have the latest list of persons featured in this series, but here are other ones I know about: Madeleine L’Engle, Joan Chittister, Dietrich Bonhoeffer, Martin Luther, Kathleen Norris, and Julian of Norwich.
These volumes provide excellent entrees into these persons. They are good for your own personal study, and they can also be easily used in small-group formation.
I’m sure you can find the complete series at the Augsburg Books website. Enjoy!