The fact that this book was a best seller in France suggests that humanity's 800 years of fascination with Francis of Assisi, the man who wrote the "Canticle of the Sun," is still intense. The writer -- a novelist and diarist, the author of 40 books, an American expatriate in Paris -- reveals in this subtle study of a man of intense faith the depths of his own faith in Catholicism, which he embraced in 1916.

Many readers will find Julien Green elusive. He relates much about the history that was being made in the years 1182 to 1226, during which Francis lived. But the complexity of the times and the contradictions in Francis' character and viewpoints do not yield a simple story. Indeed Green admits that "the further we press into Francis' life the more he tends to elude us. His very simplicity baffles our desire to understand him."

Green nonetheless has given us a solid but creative life of the Poverello. He is neither excessively pious (though he is openly reverential to Francis) nor inordinately scholarly. But he will annoy some by his habit of adopting one theory among many concerning disputed aspects of Francis' career without informing the reader of the range of opinions or even the books in which they are discussed.

Green's portrait of St. Francis does not try to conceal the extremist positions that the zealot of Assisi frequently embraced. Francis' obsession with poverty for the members of his order, his fasts and penances and his excessive reaction to sexual sins are noted by Green, although he seems reluctant to point out that some of Francis' attitudes on these and other points are more Manichaean than Christian.

"God's Fool" tries to situate Francis in a turbulent era that was plagued by fanatical religious sects and irresponsible enthusiasts for the Crusades. But the background, richly described in a series of vignettes, seems almost irrelevant to Francis, who as a mystic and prophet almost lived apart from anything that did not relate directly to his intense preoccupation with Christ -- especially in His passion and in the sufferings of His church.

Green, who obviously has had a lifelong devotion to St. Francis, tends to rhapsodize about the man he calls "the most lovable of the saints" and "the only true Christian in history."

But Green also makes it clear that Francis was really not a dreamer talking with the animals or calling the birds his brothers. He was harsh and severe. In his last years, for example, he felt strongly against those in Rome who, he felt, watered down his "brotherhood" into just another legally organized religious order. He advanced ideas about the disciplining of the body that many good Christians today would feel are un-Christian.

But Francis remains nonetheless the beloved troubadour whose life resonates in every Christian soul. No generation will ever get tired of reading about him because his agony and his aspirations remind us of the foolishness and the slavery of our attachments to earthly possessions.

The maxims of St. Francis reflect the noblest ideals of our finest moments. He reminds us of what we, too, with God's grace, could have become and, we sometimes are able to admit, should have become.