One such teaching ordered death for apostates. "It was done at the service of the imperial state. The teachings are products of their time," Banna said amid the dust and clutter of his library in a musty building in central Cairo. The 16,000 books in his library, most of them in Arabic, are neatly labeled with white tags.
"We can now create our own rules, based on the Koran," Banna said. "Some rules have no reason to survive as history evolves. This is an old story in all religions."
In one of his 30 books, author Gamal Banna argued that head coverings for women were a continuation of tribal traditions pre-dating the birth of Islam 1,400 years ago and were not mandated by the Koran. Banna has drawn particular interest because his brother was the founder of the radical Muslim Brotherhood.
(Dana Smillie For The Washington Post)
Armed with his notion of a dynamic Islam, he assaults some of the most widely promoted current fashions. He speaks in a curiously lighthearted tone, considering the seriousness of the criticism he is facing.
The notion of an Islamic state, Banna contends with a laugh, contradicts the foundation of Islam as a community of believers. The use of old Islamic teaching to justify the rule of kings and dictators has made Muslims submissive as well as exclusionary toward women, he added.
The recent focus on jihad as a justification for violent means of change also departs from the emphasis in the Koran on jihad as a moral struggle, Banna asserts. In that vein, bin Laden is using the concept "to give a religious covering to a political struggle."
Banna's critics are especially rankled by his notion that some of the post-Koranic attributions of statements to the prophet Muhammad are invalid.
"Banna's culture and education do not qualify him to understand the Koran and the Sunnah in a scientific way," said Abdul-Moti Bayoumi, a member of the Islamic Research Council. "He is not an Islamic thinker. Islamic scholars have long distinguished what is true and false in the Sunnah. I had memorized the Koran by the time I was 9 years old."
Despite the criticism, Banna's 30 books have caught the eye of observers around the world. A self-styled liberal Islamic Web site in Indonesia noted that Banna battles the idea that Islam is "political and power-oriented." Some rivals cite his recent meeting in Cairo with former secretary of state Madeleine K. Albright as evidence that his ideas are more attractive to Westerners than to Egyptians.
"He makes Westerners feel good," said Fahmy Howeidy, a commentator for Al-Ahram.
Banna acknowledges that, formally, he is not an Islamic scholar. "Unfortunately, I did not memorize the Koran," he said. "But I have read, and am serious about what I do. The point of freedom is not to let important subjects be monopolized by the few."
Banna is 13 years younger than his brother and spent much of his early adulthood in labor union activity, not Islamic studies. His first book, published in 1945, was on social welfare. President Gamal Abdel Nasser banned his 1952 book "Rationalization of Renaissance" because it labeled Nasser's takeover of Egypt as a coup.
Banna eventually drifted into state-controlled labor union activity and was a professor at a labor institute.
He insisted that despite efforts to contrast him with Hassan, his brother's thinking would have evolved over time. "He wrote 50 years ago. He would agree with me now, if he had lived," he said. Hassan Banna, who had founded the Muslim Brotherhood in 1928, was killed by Egyptian secret police in 1949 in retaliation for the Brotherhood's assassination of Prime Minister Mahmoud Fahmi Nuqrashi.
Gamal Banna says he is unafraid of the hot political climate within Islam and threats that his ideas and critiques of the violent extremes might attract. "Remember, to be a martyr is good," he said with a smile. "Anyway, I am so old, death is not far off."