By Leroy Lawson The Best American Spiritual Writing 2007, ed. Philip Zaleski (Boston, New York: Houghton Mifflin, 2007). The title raises several questions, doesn”t it? What exactly is “spiritual” writing? How do you decide what”s the best? And who is qualified to say? Philip Zaleski”s anthology doesn”t answer. The literary range is wide: essays, poetry, meditations, biographies. The sources are varied: Buddhism, Christianity, atheism, New Age, Islam, and to be determined. The quality is, as you would expect, uneven. But the reader who perseveres to the end will be rewarded, for there, in the penultimate selection, is Garry Wills objecting