Teresa of Avila's Interior Castle is one of the most celebrated books of Christian mysticism ever written. In this new edition, the classic translation by E. Allison Peers is united with fresh spiritual commentary by Dennis Billy, C.Ss.R., making it the only edition of this work to provide spiritual nourishment in an accessible form while remaining completely faithful to Teresa's mystical vision. Remarkably simple both in style and structure, Teresa's Interior Castle begins with the vision of the soul as a "castle made of a single diamond. . . in which there are many rooms, just as in Heaven there are many mansions." Building on this image, Teresa constructs a work of stunning spiritual and psychological wisdom. In his commentary, Dennis Billy breathes fresh air into this timeless work by examining Teresa's thought in its historical context and summarizing her teaching in a brief and straightforward manner.