Composing a handbook on the spiritual life is not altogether different from writing a work of art, music, or painting. A real manual must not start from a rigid framework or pretend that the rules it proposes are complete, infallible, and always and everywhere valid. Yet such "rules", precisely because they are rules, are usually the result of a long experience lived first by those who had a sense of the beautiful and then by larger groups and circles. In this manner the original experiences evolve into a tradition. -From the Introduction
