All lovers of the spiritual life know the name Rumi, great mystic Sufi poet. But until now, only a scholarly few were aware of the gifts of his father, Bahauddin, 12th-century Persian religious leader. Coleman Barks, poet and admirer of Rumi, and John Moyne, a Persian linguist, have collaborated to correct this deficit and introduce Bahauddin to a more popular audience.

Bahauddin's book, translated and interpreted by the co-authors, was originally called The Maarifa, a word signifying gnosis. That its text is not only mystical but often downright perplexing can give the reader a notion of the Sufi concept of knowledge, more like that of the great Zen Masters than that of, say, St. Augustine.

The book's words swim with meaning, like bright fish that elude us in a clear pond. It's so near to our grasp, yet so far from any possibility of being actually caught and examined. Take almost any passage at random: "A student of mine said, in the early spring it's more healthy to go naked. Not for everyone, I reminded him. Unseen influences have infinite ways of developing temperament, desire, suggestion and motive. The hidden and the apparent worlds weave together a fabric more complex than sky and earth or root and branch, more subtle than sunlight and season."

Bahauddin was no stranger to the passions and variegated experiences of the world. He writes as readily about lust, including his own, as about otherworldly matters. "Most of us rejoice in desire, in sex," he writes, "we are blessed differently than the prophets." He mentions a prophet who had a strong sex urge and remarks that his baraka (divine blessing) was thus able to be shared by his offspring.

Bahauddin's book was the object of a great lesson taught to his son Rumi by the Master Shams Tabriz. Considering that Rumi had had enough of words and was ready to live them, Shams tossed The Maarifa into a fountain. Shocked at the loss of the only extant copy of his father's diary, Rumi protests, but Shams is able to recover the book, which emerges from the water completely dry. Hence, The Drowned Book.

The Drowned Book is both spiritual elucidation and poetic expression, some of it as simple as a lesson meant for a child: "Whatever you deeply love, give time to that." "What do you believe? Try to be clear enough to say that." "Good projects succeed in the company of other goodnesses."

But some of it is deep, bespeaking a wisdom springing from another place and written in a meta-language not codified by the analytic mind: "This was painful, my soul's wanting to slip out of my body to see the wonders of God. But feeling the passage through the densities of creation, through death and divine wisdom, would be exhausting. I said, I'll stay where I am."

Bahauddin stayed where he was, and produced his book. It's not exactly a roadmap, more like a trip read for the long journey - carry it with you as you wander along, and be refreshed by it.