Mother Teresa's hidden faith struggle, laid bare in a new book that shows she felt alone and separated from God, is forcing a re-examination of one of the world's best known religious figures.

The depth of her doubts could be viewed by nonbelievers and skeptics as more evidence of the emptiness of religious belief. But Roman Catholic scholars and supporters of the woman who toiled in Calcutta's slums and called herself "a pencil in God's hand" argue that her struggles make her more accessible and her work all the more remarkable.

"It shows that she wasn't a plaster-of-Paris saint who never had a doubt about God or the ultimate meaning of life," said the Rev. Richard McBrien, a University of Notre Dame theology professor and author of "Lives of the Saints." "This can only enhance her reputation as a saintly person with people who aren't easily impressed with pious stories. Those who think otherwise have a lot of learning to do about the complexities of life and about the nature of faith."

This revelation about Mother Teresa's dark years of the soul is not new. Her ordeal, laid out to a series of confessors and confidants, became public in 2003 during the investigation into her cause for sainthood, a process fast-tracked by Pope John Paul II.

But "Come Be My Light: The Private Writings of the 'Saint of Calcutta,"' to be released Sept. 4 by Doubleday, collects her thoughts in one place for the first time, inviting a closer review of her life 10 years after her death.