STIR describes the stages of spiritual development and shows how progress through these stages is best made in the context of relationships that change in nature over time.

Mindy Caliguire is the founder of Soul Care, a spiritual formation ministry that exists to increase "soul health" in the body of Christ. She serves on the leadership team of the Willow Creek Association as the executive director for Engage International. Mindy is a contributing editor for both Leadership Journal and Conversations Journal and is the author of numerous books on the topic of spiritual formation.