The Anabasis of Alexander by Arrian is considered the best source on the campaigns of Alexander the Great. However, more recently, even though modern scholars have generally preferred Arrian to other extant primary sources, this attitude towards Arrian is beginning to change in the light of studies into Arrian's method.
Arrian was born in Nicomedia (present-day İzmit), the provincial capital of Bithynia. Cassius Dio called him Flavius Arrianus Nicomediensis. In respect of his birth date, sources provide similar dates for his birth; within a few years prior to 90, 89, and 85–90 AD. The line of reasoning for dates belonging to 85–90 AD is from the fact of Arrian being made a consul around 130 AD, and the usual age for this, during this period, being forty-two years of age. (ref. pp. 312, & SYME 1958, same page). His family was from the Greek provincial aristocracy, and his full name, L. Flavius Arrianus, indicates that he was a Roman citizen, suggesting that the citizenship went back several generations, probably to the time of the Roman conquest some 170 years before.
Sometime during the 2nd century AD (117 to 120 AD) while in Epirus, probably Nicopolis, Arrian attended lectures of Epictetus of Nicopolis, and proceeded within a time to fall into his pupillage, a fact attested to by Lucian. All that is known about the life of Epictetus is due to Arrian, in that Arrian left an Encheiridion (Handbook) of Epictetus' philosophy. After Epirus he went to Athens, and while there he became known as the young Xenophon as a consequence of the similarity of his relation to Epictetus as Xenophon had to Socrates.
For a period, some time about 126 AD, he was a friend of the emperor Hadrian, who appointed him to the Senate. He was appointed to the position consul suffectus around 130 AD, and then, in 132 AD (although Howatson shows 131), he was made prefect or legate (governor) of Cappadocia by Hadrian, a service he continued for six years. The historian Cassius Dio, states that not long after the Bar Kokhba revolt in Judea had been quelled, in 135 AD, King Pharasmanes II of Iberia caused the Alani to invade neighbouring territories, including Cappadocia where their advance was robustly halted by Arrian's legions.
A second war was begun by the Alani (they are Massagetae) at the instigation of Pharasmanes. It caused dire injury to the Albanian territory and Media, and then involved Armenia and Cappadocia; after which, as the Alani were not only persuaded by gifts from Vologaesus but also stood in dread of Flavius Arrianus, the governor of Cappadocia, it came to a stop.
Arrian referred to himself as the second Xenophon, on account of his reputation and the esteem in which he was held. Lucian stated him to be:
a Roman of the first rank with a life-long attachment to learning
— quote of Lucian in P. E. Easterling, B. M. W. Knox, p. 143
This quality is identified as paideia (παιδεία) which is the quality considered to be of one who is known as an educated and learned personage, i.e., one who is highly esteemed and important.
There are eight extant works (cf. Syvänne, footnote of p. 260). The Indica and the Anabasis are the only works completely intact. His entire remaining oeuvre is known as FGrH 156 to designate those collected fragments which exist.
Arrian was a pupil of Epictetus around 108 AD, and, according to his own account, he was moved to publish his notes of Epictetus' lectures, which are known as Discourses of Epictetus, by their unauthorized dissemination. According to George Long, Arrian noted from Epictetus' lectures for his private use and some time later made of these, the Discourses. Photius states that Arrian produced two books the Dissertations and the Discourses. The Discourses are also known as Diatribai and are apparently a verbatim recording of Epictetus' lectures.
The Enchiridion is a short compendium of all Epictetus' philosophical principles. It is also known as a handbook, and A Mehl considers the Enchiridion to have been a vade mecum for Arrian. The Enchiridion is apparently a summary of the Discourses.
JB Stockdale considered that Arrian wrote eight books of which four were lost by the Middle Ages and the remaining ones became the Discourses. In a comparison of the contents of the Enchiridion with the Discourses, it is apparent that the former contains material not present within the latter, suggesting an original lost source for the Enchiridion.
History of the Diadochi or Events after Alexander is a work originally of ten books; a commentary on this work was written by Photius (FW Walbank, p. 8).
Three extant fragments are the Vatican Palimpsest (of the 10th century AD), PSI 12.1284 (Oxyrhynchus), and the Gothenburg palimpsest (of the 10th century also), these possibly stemming originally from Photius.
Indica is a work on a variety of things pertaining to India, and the voyage of Nearchus in the Persian Gulf. The first part of Indica was based largely on the work of the same name of Megasthenes, the second part based on a journal written by Nearchus.
Written 136/137 AD (in the 20th year of Hadrian), Techne Taktike is a treatise on Roman cavalry and military tactics, and includes information on the nature, arms and discipline of the phalanx. The hippika gymnasia is a particular concern of Arrian in the treatise.
Another translation of the title is Ars tactica, which, in Greek, is Τέχνη τακτική.
This work has generally been considered in large part a panegyric to Hadrian, written for the occasion of his vicenallia, although some scholars have argued that its second half may have had practical use.
Cynegeticus (Κυνηγετικός),  translated as A treatise on hunting with hounds, On Hunting, or On Coursing, is a work about the Celtic sport of coursing hare with sighthounds, specifically the Celtic greyhounds: in Greek (plural) ouertragoi, in Latin (plural) vertragi.
The work was inspired by and designed as an addition to the an earlier exposition made by Xenophon, whom Arrian recognised
to be the Ancient Greek authority on the subject of hunting with scent hounds.
Ektaxis kata Alanon (Ἔκταξις κατὰ Ἀλανῶν) is a work of a now fragmentary nature; the title is translated as Deployment against the Alani or The order of battle against the Alans or referred to simply as Alanica. It is thought not have been written as a presentation of facts but for literary reasons. Pertaining to the relevant historical facts, though, while governor of Cappadocia, Arrian repelled an invasion of the Alani sometime during 135 AD, a struggle in which Arrian's two legions were victorious.
Within the work, Arrian explicitly identified the particular means of pursuing warfare as being based on Greek methods.
Ektaxis kata Alanon is also translated as Acies contra Alanos. The work was known for a time as A History of the Alani (Alanike via Photius). A fragment describing a plan of battle against the Alani was found in Milan around the 17th century which was thought at that time to belong to the History.
Sources, transmission, translations and publications
Everything known of his life derives from the 9th century writing of Photius in his Bibliotheca, and from those few references which exist within Arrian's own writings. The knowledge of his consulship, is derived at the least from literature produced by Suidas. Arnobius (c. 3rd century AD) mentions Arrian. Arrian was also known of by Aulus Gellius. Pliny the Younger addressed seven of his epistles to him. Simplicius made a copy of the Encheridion, which was transmitted under the name of the monastic father Nilus during the 5th century, and as a result found in every monastery library.
The voyage of Nearchus and Periplus of the Erythrean Sea were translated from the Greek by the then Dean of Westminster, William Vincent, and published in 1809. Vincent published a commentary in 1797 on The voyage of Nearchus. The work was also translated into French by M. Billecocq, under the auspices of the government (cf. p. 321).
^"Arrian". www.britannica.com. Retrieved 2010-01-07. Arrian born c. AD 86, Nicomedia, Bithynia [now İzmit, Tur.] died c. AD 160, Athens? [Greece].
^Stadter's suggestion that his official name was Lucius Flavius Arrianus Xenophon (Stadter, Philip (1967). "Flavius Arrianus: The New Xenophon". Greek, Roman and Byzantine Studies. Retrieved April 14, 2016.) is disproven by epigraphic evidence: Bowie, E. L. “Greeks and Their Past in the Second Sophistic.” Past & Present, 46 (1970): 25 n. 72.
^ abc"Arrian". www.britannica.com. Retrieved 2010-01-07. Arrian (born c. ad 86, Nicomedia, Bithynia [now İzmit, Tur.] died c. 160, Athens? [Greece]) Greek historian and philosopher who was one of the most distinguished authors of the 2nd-century Roman Empire.
Wolfgang Haase; Hildegard Temporini (1990). Aufstieg und Niedergang der römischen Welt: Geschichte und Kultur Roms im Spiegel der neueren Forschung, Volume 2; Volume 34. Walter de Gruyter. p. 228. ISBN3-11-010376-1. Arrian was of Greek stock, from the provincial aristocracy of Bithynia. His full name, L. Flavius Arrianus, demonstrates that he was a Roman citizen and suggests that the citizenship went back several generations, probably to the triumphal period. Arrian’s home city was the Bithynian capital, Nicomedia, where he held the priesthood of Demeter and Kore, its patron deities.
Arrian; Sélincourt, Aubrey De (1971). The campaigns of Alexander. Penguin Classics. p. 13. ISBN0-14-044253-7. Flavius Arrianus Xenophon, to give him his full name, was a Greek, born at Nicomedia, the capital of the Roman province of Bithynia, probably a few years before A.D. 90.
Grant, Michael (1992). Readings in the classical historians. Scribner's. p. 544. ISBN0-684-19245-4. ARRIAN: GREEK HISTORIAN Arrian was an approximate contemporary of Appian, born about AD 95. Like him a Greek, he came from Nicomedia (İzmit) in Bithynia (north-western Asia-Minor) where his family was prominent.
^Heckel, Waldemar (2004). The History of Alexander. Penguin. pp. 5 & 269.
^"Arrian". www.britannica.com. Retrieved 2010-01-07. Arrian (born c. ad 86, Nicomedia, Bithynia [now İzmit, Tur.] died c. 160, Athens? [Greece]) Greek historian and philosopher who was one of the most distinguished authors of the 2nd-century Roman Empire.Wolfgang Haase; Hildegard Temporini (1990). Aufstieg und Niedergang der römischen Welt: Geschichte und Kultur Roms im Spiegel der neueren Forschung, Volume 2; Volume 34. Walter de Gruyter. p. 228. ISBN3-11-010376-1. Arrian was of Greek stock, from the provincial aristocracy of Bithynia. His full name, L. Flavius Arrianus, demonstrates that he was a Roman citizen and suggests that the citizenship went back several generations, probably to the triumphal period. Arrian’s home city was the Bithynian capital, Nicomedia, where he held the priesthood of Demeter and Kore, its patron deities.Arrian; Sélincourt, Aubrey De (1971). The campaigns of Alexander. Penguin Classics. p. 13. ISBN0-14-044253-7. Flavius Arrianus Xenophon, to give him his full name, was a Greek, born at Nicomedia, the capital of the Roman province of Bithynia, probably a few years before A.D. 90.Grant, Michael (1992). Readings in the classical historians. Scribner's. p. 544. ISBN0-684-19245-4. ARRIAN: GREEK HISTORIAN Arrian was an approximate contemporary of Appian, born about AD 95. Like him a Greek, he came from Nicomedia in Bithynia (north-western Asia-Minor) where his family was prominent.
^ abcM.C. Howatson (2013-08-22). The Oxford Companion to Classical Literature (p.73). Oxford University Press, 22 Aug 2013 (reprint). ISBN978-0-19-954855-2. (.... Enchiridion a summary of the Discourses)
^PA Stadter - (1978). "The Ars Tactica of Arrian: Tradition and Originality – Classical Philology Vol. 73, No. 2 (Apr., 1978), pp. 117-128". Classical Philology. The University of Chicago Press. 73 (2): 117–128. JSTOR268990.
^L Boia – Great Historians from Antiquity to 1800: An International Dictionary, Volume 1 Greenwood Press, 1 Jan 1989 ISBN0-313-24517-7 (ed. first source for Tilliborus, found here  (Retrieved 2015-04-04]