The ancient formula lex orandi, lex credendi might be translated: as we pray, so we believe. Unfortunately, there has been a split between theology and spirituality, and many theologians haven't had much to say about spirituality. Contemporary theologians are more known for talking about God than talking with or listening to God. Conversely, the many books on spirituality often are quite thin on theology. So how are we to discern what makes for good spirituality? I like the three principles suggested by Eugene Peterson: spirituality, if it is to be Christian spirituality, should be Christ-centered, biblically based, and rooted in a living Christian tradition. Not that Christians can't or shouldn't learn from the spiritualities of other religions. But the least helpful forms of spirituality are those which are not rooted anywhere.

Spirituality should also reflect and respond to the realities of life. Lawrence Cunningham says all spiritualities should be subjected to these questions: Can you teach it to your children? Does it carry over into more loving relationships with people not part of your nurturing community? And will it help you in times of profound crisis?

To varying degrees, the books reviewed here measure up to Peterson's tests. You'll have to judge how they stack up with real life.

Keeping Silence: Christian Practices for Entering Silence.
By C. W. McPherson. Morehouse, 96 pp., $12.95.

While she was a university student, Joyce Maynard observed that her generation didn't notice the radio was on until someone turned it off. And that was before cable TV, the Internet and cell phones. For her generation, noise is the norm; silence is not just abnormal but unbearable. Keeping Silence is an antidote for a world in which we are bombarded with sound and are unsettled by silence. The author of this manual on silence, an Episcopal priest, regularly encourages his parishioners to practice various spiritual disciplines. But when he encourages them to practice a few minutes of silence each day during Advent and Lent, he says, he might as well urge them to memorize the Gospel of Luke. Some simply find it impossible to turn off either external noise from the environment or internal noises from their own psyche. A student of both the patristic period and the Middle Ages, McPherson draws from the rich resources of both eras, suggesting many exercises to aid in keeping silent, from Benedictine rumination and breath counting to cloister walking and the stations of the cross. Silence, of course, isn't an end in itself; being still and sensing the presence of God is. "Resources for further study" is a useful annotated bibliography at the back of the book.

The Rhythm of God's Grace: Uncovering Morning and Evening Hours of Prayer.
By Arthur Paul Boers. Paraclete, 165 pp., $15.95.

Boers is numbered among those contemporary Christians who are calling the church back to fixed-hour prayers, which have their roots in the Jewish tradition. But as a concession to the busyness of our context, Boers suggest morning and evening prayers only, not the monastic regiment of eight "hours" of prayer from matins (or vigils) to compline. Boers finds these benefits, among others, in adhering to fixed times of prayer: it keeps him in touch with the rhythms of the day, it exposes him to scripture and it keeps him connected to other Christians around the world who keep a constant chain of daily prayers going as the earth revolves. Besides, when we pray "by the book," the book helps us pray when we don't know how or can't. Boers, a Mennonite pastor and professor and a Benedictine oblate, encourages praying in groups. He suggests numerous book sources for daily prayers.