To render more accessible the riches of the The Encyclopaedia of Islam (the second edition consists of seven fat volumes published since 1954, and it's only up to the letter "n"), its editors have published a single-volume manual. In contrast to the many-paged entries of the Encyclopaedia, entries in the Desk Reference consist mostly of two to four lines. The result is an extremely useful introduction to the major characters, places, institutions, and customs of the Muslim world.
Though barebone, the entries nonetheless hint at the fascination of the full-scale articles from which they derive. Look up "Sabbath," for example, and learn that the lack of an Islamic day of rest follows from the stringent Islamic ban on anthropomorphism (God could not have needed a day of rest).
Given the orientalist pedigree of the Encyclopaedia, it probably comes as no surprise that the editors deal more consistently with medieval subjects than with modern ones. Indeed, post-World War II is striking in its inconsistency. Shah Mohammed Reza Pahlavi has a very long entry while the Ayatollah Khomeini is completely absent. One Egyptian fundamentalist (Hasan al-Banna) shows up and another (Sayyid Qutb) does not. But this is a mere cavil. The Islamic Desk Reference's major accomplishment is to offer an accurate and fast access to the history and religion of the Muslim peoples.