Ibn Khordadbeh

Abu'l-Qasim Ubaydallah ibn Abdallah ibn Khordadbeh () (c. 820 – 912), better known as Ibn Khordadbeh or Ibn Khurradadhbih, was a Persian geographer and bureaucrat of the 9th century. He is the author of the earliest surviving Arabic book of administrative geography. 
Biography.
He was the son of Abdallah ibn Khordadbeh, a prominent Abbasid general, himself the son of a Zoroastrian convert to Islam. Ibn Khordadbeh was appointed "Director of Posts and Intelligence" for the province of Jibal in northwestern Iran under the Abbasid Caliph al-Mutammid (ruled 869–885). In this capacity ibn Khordadbeh served as both postmaster general and the Caliph's personal spymaster in that vital province.
Around 870 ibn Khordadbeh wrote "Kitāb al Masālik w’al Mamālik" ("The Book of Roads and Kingdoms") (with the second edition of the book being published in 885). In this work, ibn Khordadbeh described the various peoples and provinces of the Abbasid Caliphate. Along with maps, the book also includes descriptions of the land, people and culture of the Southern Asiatic coast as far as Brahamputra, the Andaman Islands, peninsular Malaysia and Java. The lands of Tang China, Unified Silla (Korea) and Japan are referenced within his work. He was also one of the earliest Muslim writers to record Viking trade to the east: 'merchants called "Rus" traded in the Black Sea and the Caspian Sea, transporting their merchandise by camel as far as Baghdad.
Ibn Khordadbeh clearly mentions Waqwaq twice: "East of China are the lands of Waqwaq, which are so rich in gold that the inhabitants make the chains for their dogs and the collars for their monkeys of this metal. They manufacture tunics woven with gold. Excellent ebony wood is found there." And again: "Gold and ebony are exported from Waqwaq."
Claudius Ptolemy, Greek and Pre-Islamic Iranian history have clear influence on the work.
It is one of the few surviving sources that describes Jewish merchants known as Radhanites.
Khordadbeh wrote other books. He wrote around 8–9 other books on many subjects such as "descriptive geography" (the book "Kitāb al Masālik w’al Mamālik"), "etiquettes of listening to music", "Persian genealogy", cooking", "drinking", "astral patterns", "boon-companions", "world history", "music and musical instruments". The book on music had the title "Kitāb al-lahw wa-l-malahi" which is on musical matters of Pre-Islamic Persia.