The "Interior Castle" by Teresa of Ávila is a significant work of Spanish mysticism, published in 1577. In this book, the author describes the soul as a glass vessel in the shape of a castle, which encompasses seven inner mansions. Each of these mansions represents a stage on the path to spiritual self-education and union with God. Teresa of Ávila, who is venerated as a Doctor of the Church and a saint, emphasizes that true spirituality consists not only in devotional pleasures but also in the execution of actions. This book offers a profound guide to the inner journey and the practical implementation of faith in everyday life. It is of great importance for those interested in mysticism as well as for individuals seeking to engage with spiritual development.