Discussed in this essay:

The Islamic Enlightenment: The Struggle Between Faith and Reason, 1798 to Modern Times, by Christopher de Bellaigue. Liveright. 432 pages. $35.

The Idea of the Muslim World: A Global Intellectual History, by Cemil Aydin. Harvard University Press. 304 pages. $29.95.

The Story of Reason in Islam, by Sari Nusseibeh. Stanford University Press. 288 pages. $29.95.

Letters to a Young Muslim, by Omar Saif Ghobash. Picador. 272 pages. $22.

Early in January 1989, a man who had led a revolution wrote to a man who was trying to bury one. “Mr. Gorbachev!” the letter said. “Reality must…