"The Forty Rules of Love" (Viking, 354 pages), by Elif Shafak: Before he became a world-famous poet and Sufi mystic, a religious scholar named Jalal ad-Din Rumi struggled with a feeling of inexplicable emptiness. Despite his thousands of admirers and disciples, Rumi felt something was missing in his life.

A wandering dervish called Shams of Tabriz came as the answer to Rumi´s prayers. The pair were kindred spirits and intellectual equals who reveled in discussing and debating matters of God, man and divine love. Their friendship, in 13th-century Anatolia, transformed Rumi.

The tale of their fated meeting, spiritual companionship and tragic parting is beautifully recounted in the new novel "The Forty Rules of Love," by Turkish writer Elif Shafak. Their saga unfolds in a manuscript being read by Ella, an unhappy American housewife who recently started working for a literary agency. Shafak goes back and forth — from present-day Northampton, Mass., to Konya, Turkey, in the mid-1200s — and tells the parallel stories from the perspective of various characters.

Shafak draws on facts from Rumi and Shams´ biographies and brings them to life with deft storytelling. The 40 rules in the title refer to a list of principles that Shafak´s rendition of Shams compiled while roaming the Earth. They include gems like: "What does patience mean? It means to look at the thorn and see the rose, to look at the night and see the dawn. ... The lovers of God never run out of patience, for they know that time is needed for the crescent moon to become full."

The Sufi perspective on Islam — and how drastically it differs from that of fundamentalists — is a major theme. At one point, a judge scolds Shams for his "complicated" view of life, saying: "Human beings are simple creatures with simple needs. It falls upon the leaders to see to their needs and make sure they do not go astray. That requires applying the sharia (Islamic law) to perfection." Shams, in typical fashion, responds: "The sharia is like a candle. It provides us with much valuable light. But let us not forget that a candle helps us to go from one place to another in the dark. If we forget where we are headed and instead concentrate on the candle, what good is it?"

While the historical story line is thoroughly engrossing, the same cannot be said for sections of the book dealing with Ella. Her character and those of her family seem cliche and their dialogue stilted. Shafak, whose previous works include "The Bastard of Istanbul," could have done without the modern subplot and the book would have been stronger for it. Nevertheless, "The Forty Rules of Love" is a captivating and wise book.

San Francisco Chronicle