THE guiding principle in transliterating Persian and Arabic words in this biography has been to ease the difficulties of non-specialist readers. Persian words have been rendered into Latin script according to the standard Iranian pronunciation of today. Words of Arabic origin that have entered English parlance, such as hijab or Kaaba, have retained their common spellings. Proper names of Arab historical figures have been transliterated according to a simplified version of the system used by the International Journal of Middle East Studies. Diacritic marks have been entirely omitted, except in the bibliographical citations, where a stricter system of transliteration, which adheres more closely to the titling of articles or books in library catalogues, has been used.