Eight centuries after his death, Francis of Assisi remains one of Christianity's most popular saints.
Antiwar protesters hold up St. Francis as an example for peacemakers. During the Crusades, he traveled behind enemy lines, where he made friends with Muslim leaders.
Spiritually inclined environmentalists say prayers to Francis, patron saint of ecology.
And to those who believe drugs, sex and money have corrupted society and weakened the faithful, Francis' story offers a radical but appealing path to God. The son of a wealthy merchant, he gave up his worldly possessions, including the clothes on his back, to humble himself and develop a more intimate relationship with Jesus.
By the end of his life at about 45 years of age, Francis, who was never a priest, had 20,000 followers -- a group that has lived on as the Franciscans.
Kenneth Baxter Wolf, a history professor at Pomona College, is less of an admirer. "There was something about Francis that bugged me for a long time," said Wolf, author of a new book, "The Poverty of Riches: St. Francis of Assisi Reconsidered," which is being released this month.
In his book, Wolf criticizes St. Francis for imitating the poor, an act that brought him adulation, rather than using his resources to alleviate poverty.
For instance, Francis "hung out with lepers to make a statement to his former social class," said Wolf. "This did nothing for the lepers, but everything for Francis."
Wolf contends that Francis' self-imposed poverty concentrated too much on his own relationship with God, not on helping those around him.
The book points up a basic and continuing divide within Christian thinking: Should religiously motivated people focus their efforts on improving their society or on their personal relationships with God?
"The book is not simply an iconoclastic poke in the eye," Wolf said. "The kind of spirituality that Francis represents may be doing more harm than good, and it's time Christians and other admirers of Francis ruminated about that for awhile."
Such criticism isn't likely to bother members of the religious order that Francis founded, said Friar Francisco Nahoe of the National Shrine of St. Francis of Assisi in San Francisco.
"At least Professor Wolf has made an attempt to treat seriously the life and activities of a remarkable man," Nahoe said.
What troubles Nahoe more than Wolf's criticism is the tendency in society at large "to reduce the spiritual and psychological complexity of St. Francis into a mere pop icon more fit to adorn the lawns of suburban tract housing than to provoke debate" about wealth and consumption.
A second recent book about St. Francis, "Reluctant Saint: Francis of Assisi," also is designed to transform the image of the saint from a pious religious icon to a three-dimensional historical figure.
"Saints tend to have their humanity erased, and they become figures out of a Hollywood movie," said Donald Spoto, the book's author. "Francis was a flesh-and-blood human being."
Nahoe said he has similar frustrations: "Sentimentality so disfigures the historical Francis as to make his commitment to penance seem more like the lifestyle of a pleasant medieval hippie than the constant struggle against sin of a sincere and sometimes scary penitent," he said.
Father James Gardiner, a Franciscan friar who is director of Graymoor Spiritual Life Center in New York, said that part of Francis' long-lasting popularity reflects the paradox of his chosen life. It's something that seems so simple and appealing but is difficult to do, he said.
"Lots of people get to the point in their lives where they're looking for what Francis had," Gardiner said. "He had no turf to protect, no possessions to guard. They say, 'We really wish we could be like that.' They could -- if they would give up everything."