Clifford Geertz, an influential American anthropologist best known for developing the theory of “interpretive anthropology”, is renowned for his comparative study of Islam in Indonesia and Morocco, most notably expressed in his influential book, “Islam Observed: Religious Development in Morocco and Indonesia” (1968). Geertz’s work focuses on how the “single creed” of Islam is expressed quite differently in contrasting cultural contexts, using Morocco and Indonesia to illustrate these divergences. His core insight is that religion, including Islam, cannot be understood in abstraction or solely through doctrine, but must be examined as it is embedded in lived social and cultural realities. Geertz famously argued that culture is a “web of meaning,” and that analyzing religious life requires what he called “thick description” — detailed, context-rich ethnography that looks beyond surface behaviors to deeper symbolic meanings. Geertz showed that in Morocco, Islam developed toward activism, moralism, and individualism, while in Indonesia it leaned toward aestheticism, inwardness, and dissolution of the self. He used case studies — such as the market (suq), mosque, and the pesantren in Indonesia — to analyze how Islamic beliefs and practices are woven into everyday social institutions. His method placed emphasis on how individual and collective identities are constructed differently within each Islamic context. Geertz warned against “defining” Islam monolithically, insisting instead on observing how faith supports varying kinds of social life depending on the respective historical, cultural, and political environments. Geertz’s comparative approach has been both influential and critiqued. Critics have argued that he sometimes overly generalized or neglected political dimensions, particularly in Indonesia where he underplayed the relevance and potential of political Islam. Others noted that his focus was sometimes more on the symbolic and cultural dimensions, at the expense of social or gendered dynamics, especially in his treatments of Moroccan Islam. Nevertheless, his work remains a model for culturally grounded, anthropologically sensitive studies of Islam, and has spurred ongoing debates about how best to study Islamic societies and religious change. Geertz’s concepts — particularly “thick description” and culture as a “web of meaning” — have profoundly shaped not only Islamic Studies but anthropology and the humanities at large. “Islam Observed” is still considered essential reading for anyone seeking to understand religious variety within the Islamic world and the methodological challenges of comparative studies of religion. Geertz’s legacy is that Islam is not a monolithic or universal experience but a faith continually interpreted through multiple, changing webs of meaning specific to context.