Encyclopaedia Iranica is the most renowned reference work in Iranian studies. Founded by the late Professor Ehsan Yarshater and edited at the Ehsan Yarshater Center for Iranian Studies at Columbia University, this monumental international project brings together the scholarship about Iran of thousands of authors around the world.

The Oxford Handbook of Ancient Iran provides up-to-date, authoritative essays on a wide range of topics, from the earliest Paleolithic settlements in the Pleistocene era to the Arab conquest in the 7th century AD. The volume, authored by specialists based both inside and outside of Iran, is divided into sections covering prehistory, the Chalcolithic, the Bronze Age, the Iron Age, the Achaemenid period, the Seleucid and Arsacid periods, the Sasanian period, and the Arab conquest. In addition, more specialized chapters are included, which treat numismatics, religion, languages, political ideology, calendrics, the use of color, textiles, Sasanian silver and reliefs, and political relations with Rome and Byzantium.

The Oxford Handbook of Iranian History is a guide to Iran's complex history. The book emphasizes the large-scale continuities of Iranian history while also describing the important patterns of transformation that have characterized Iran's past. Each of the chapters focuses on a specific epoch of Iranian history and surveys the general political, social, cultural, and economic issues of that era. This volume is a collaborative exercise among scholars specializing in a variety of sub-fields, and across a number of disciplines, including history, art history, classics, literature, politics, and linguistics. Here, readers can find a reliable and accessible narrative that can serve as an introduction to Iranian studies. While the number of monographs published within specialized subfields of Iranian history continues to proliferate, there have been, to date, no books that attempt to produce a comprehensive single-volume history of Iranian civilization.

A Literary History of Persia remains the standard work in the English language on the history of Persia and Persian literature. Browne's famous work, first published in 1902, spans four volumes and took about twenty-five years to write. Volume 1 chronicles trends and events in Persian literature from the beginning to Ferdowsi (1000 A.D.); volume 2 covers the period between Ferdowsi and Saʿdi (1000-1290); volume 3 deals with the Ilkhanid and Timurid periods (1265-1502); and the last volume documents Persian literature in modern times (1500-1924).

The Cambridge History of Iran, in seven volumes, is a survey of Iranian history. The seven volumes cover the history and historical geography of the land, which is present-day Iran and other territories inhabited by peoples of Iranian descent, from prehistoric times up to the present. Volume 1, edited by W. B. Fischer, examines the land of Iran from the vantage point of historical geography. Edited by Ilya Gershevitch, volume 2 studies the history of the Median and Achaemenian periods. Volume 3, in two parts, covers the Seleucid, Parthian, and Sasanian periods and is edited by Ehsan Yarshater. Volume 4, edited by Richard N. Frye, focuses on the period from the Arab invasion to the Saljuqs. Edited by J. A. Boyle, volume 5 is dedicated to the history of the Saljuq and Mongol periods. Volumes 6 and 7, edited by Peter Jackson, Laurence Lockhart, Peter Avery, Gavin Hambly, and Charles Melville, examine different aspects of the history of Iran from the Timurid and Safavid periods until the 1979 revolution. 

The Encyclopaedia of Islam, published by Brill, is the standard reference work in Islamic studies. The first edition was published between 1913-1938, the second from 1954 until 2005, and the third was begun in 2007.

Gazetteer of the Persian Gulf, Oman and Central Arabia Online is the full-text searchable online version of the work compiled and written by John Gordon Lorimer (1870-1914), an official of the Indian Civil Service. The Gazetteer is one of the most important European primary sources for studying the modern Gulf region from the 17th to the early 20th century.

Supplement to the Persian Gulf Gazette was instituted to administer British interests in the Gulf. The collection covers the period between 1953-1972.

Indo-European Etymological Dictionaries Online (IDEO) reconstructs the lexicon for the most important languages and language branches of Indo-European. It is a rich and voluminous online reference source for historical and general linguists. Dictionaries can be cross-searched, with an advanced search for each individual dictionary enabling the user to perform more complex research queries. Each entry is accompanied by grammatical info, meaning(s), etymological commentary, reconstructions, cognates, and extensive bibliographical information.

Platts Dictionary of Urdu, Classical Hindi, and English was published in 1884. It includes Perso-Arabic, Devanagari, and Roman alphabets. The data conversion and presentation of the online version of the dictionary was sponsored by the University of Chicago, the University of Michigan, and the University of Wisconsin-Madison with support from the U.S. Department of Education and the Japan Society for the Promotion of Science. Date for this dictionary was most recently updated in February 2015. 

The Oxford History of the Ancient Near East, of which the fifth and final volume deals with the history of the Persian Empire, covers the period from the second half of the 7th century BC until the campaigns of Alexander III of Macedon in 336-323 BC.