Thailand is usually closely associated with Buddhism, but since 1998 the country has been one of the observer members of the Islamic Conference Organization, and senior figures in the present and previous governments have been Muslim. Some 8 percent of the population is Muslim, and in the three southernmost provinces of the country they constitute a majority. Islam is ever more visible in Bangkok, where the demographic increase of Muslims is marked.

Michel Gilquin, a sociologist specializing in the study of Muslim societies and a resident of Morocco, examines the origins of Islam in...