When I wrote my biographical novel Sister Teresa, based on the life of the sixteenth-century saint Teresa of Ávila, I wanted to be respectful of the millions of people who venerate her. I didn't want to besmirch her reputation, yet I was anxious to create a vivid, exciting character and a saleable book. My previous novel, Frida, based on the life of Frida Kahlo, had been a bestseller. However, Kahlo was a sexual and social rebel, so turning her into a colorful character was relatively easy. In the case of Teresa, I had to humanize the saint and also build into the plot the adventure, romance, sexual tension, and mystery that a novel requires.

What drew me to Teresa was her spiritual message. At the beginning of Las Moradas (“The Interior Castle”) she invites us to “consider our soul to be like a castle made entirely out of a diamond or of very clear crystal, in which there are many rooms, just as in heaven there are many dwelling places” (1980, p. 283). By moving inward, through the different chambers, we eventually reach the innermost room, where God resides. For Teresa, finding God was not a matter of rituals and prayers mechanically performed, but of moving deeper into oneself, toward one's own spiritual core.

In 1562, Teresa formed a new religious order, the Discalced Carmelites, which fostered cultivation of the inner life.