About the book (from Wikipedia):
The Anabasis of Alexander was composed by Arrian of Nicomedia in the second century AD, most probably during the reign of Hadrian. The Anabasis (which survives complete in seven books) is a history of the campaigns of Alexander the Great, specifically his conquest of the Persian Empire between 336 and 323 BC. Both the unusual title “Anabasis” (literally “a journey up-country from the sea”) and the work’s seven-book structure reflect Arrian’s emulation (in structure, style, and content) of the Greek historian Xenophon, whose own Anabasis in seven books concerned the earlier campaign “up-country” of Cyrus the Younger in 401 BC.
The Anabasis is by far the fullest surviving account of Alexander’s conquest of the Persian empire. It is primarily a military history, reflecting the content of Arrian’s model, Xenophon’s Anabasis; the work begins with Alexander’s accession to the Macedonian throne in 336 BC. Arrian’s chief sources in writing the Anabasis were the lost contemporary histories of the campaign by Ptolemy and Aristobulus and, for his later books, Nearchus. One of Arrian’s main aims in writing his history seems to have been to correct the standard “Vulgate” narrative of Alexander’s reign that was current in his own day, primarily associated with the lost writings of the historian Cleitarchus.