Interior Castle is a guide for spiritual development through service and prayer. The work was inspired by Teresa's vision of the soul as a diamond in the shape of a castle containing seven mansions, which she interpreted as the journey of faith through seven stages, ending with union with God. The book was written as a practical blueprint for "seekers" who want to experience prayer as mystical union with God.

Teresa's exposure of how she was blessed with contemplation illuminates the Catholic theologies of grace, the sacraments, humility and ultimately love. It contains the basis for what she felt should be the ideal journey of faith. The first English translation was published in 1675 and the second in 1852.

This case laminate collector's edition includes a Victorian inspired dust-jacket.