The Ḥudūd al-ʿĀlam (Arabic: حدود العالم "Boundaries of the World" or "Limits of the World") is a 10th-century geography book written in Persian by an unknown author from Jowzjan. The title in full is حدود العالم من المشرق الی المغرب (Ḥudūd al-ʿĀlam min al-Mashriq ilá l-Maghrib, "The Boundaries of The World from The East to the West").
In English, the title is also translated as "The Regions of the World" following Vladimir Minorsky's 1937 translation, in which he commented on the title as follows: "The word ḥudūd (properly 'boundaries') in our case evidently refers to the 'regions within definite boundaries' into which the world is divided in the Ḥ.-'Ā., the author indicating with special care the frontiers of each one of these areas, v.i., p. 30. [As I use the word "region" mostly for nāḥiyat it would have been better, perhaps, to translate Ḥudūd al-Ālam as "The limited areas of the World".]"
Finished in 982 CE, it was dedicated to Abu'l Haret Muhammad, the ruler of the Farighunids. Its author is unknown, but Vladimir Minorsky has surmised that it might have been written by the enigmatic Šaʿyā bin Farīghūn, author of a pioneer encyclopedia of the sciences, the Jawāmeʿ al-ʿUlum, for an amir of Čaghāniān on the upper Amu Darya in the mid-10th century. The available text of Ḥudūd al-ʿĀlam is part of a larger manuscript which contains other works:
The Ḥudūd al-ʿĀlam contains information about the known world. The anonymous author reports about different countries (nāḥiyat), people, languages, clothing, food, religion, local products, towns and cities, rivers, seas, lakes, islands, the steppe, deserts, topography, politics and dynasties, as well as trade. The inhabited world is divided in Asia, Europe and "Libya" (i.e. the Maghreb). The author counts a total of 45 different countries north of the equator.
The author never visited those countries personally, but rather compiled the book from earlier works and tales. He did not indicate his sources, but researchers deduced some, for example Estakhri Book of the Paths and Provinces (Arabic: كتاب المسالك والممالك), or the works of Abu Abdallah al-Jayhani and Ibn Khurdādhbih.