Encyclopaedia of Islam

The Encyclopaedia of Islam (also French: Encyclopédie de l'Islam and German: Enzyklopädie des Islām; EI is a common abbreviation in all three languages) is a reference work that facilitates the academic study of Islam. It is published by Brill and provides information on various aspects of Islam and the Islamic world. It is considered to be the standard reference work in the field of Islamic studies. The first edition was published in 1913–1938, the second in 1954–2005, and the third was begun in 2007.

According to Brill, the EI includes "articles on distinguished Muslims of every age and land, on tribes and dynasties, on the crafts and sciences, on political and religious institutions, on the geography, ethnography, flora and fauna of the various countries and on the history, topography and monuments of the major towns and cities. In its geographical and historical scope it encompasses the old Arabo-Islamic empire, the Islamic countries of Iran, Central Asia, the Indian sub-continent and Indonesia, the Ottoman Empire and all other Islamic countries".

EI is considered to be the standard reference work in the field of Islamic studies. Each article was written by a recognized specialist on the relevant topic.^{[citation needed]}

The most important, authoritative reference work in English on Islam and Islamic subjects. Includes long, signed articles, with bibliographies. Special emphasis is given in this (EI2) edition to economic and social topics, but it remains the standard encyclopedic reference on the Islamic religion in English.

— Librarian Suzanne K. Lorimer, Yale University Library

The most important and comprehensive reference tool for Islamic studies is the Encyclopaedia of Islam, an immense effort to deal with every aspect of Islamic civilization, conceived in the widest sense, from its origins down to the present day... EI is no anonymous digest of received wisdom. Most of the articles are signed, and while some are hardly more than dictionary entries, others are true research pieces – in many cases the best available treatment of their subject.

— Historian R. Stephen Humphreys

This reference work is of fundamental importance on topics dealing with the geography, ethnography and biography of Muslim peoples.