Hi /r/AskHistorians. I am a college history student taking a course called "Historical Practices," that seeks to teach students how to, for all intents and purposes, do history.
Our grade is entirely based on our research paper, which I've decided I want to write on the factors that contributed to Alexander the Great being able to conquer the area he did.
Right now we are in the process of looking for primary sources. However, my professor told me that given my time period is ancient, and that primary sources might be limited, other sources (like Plutarch) could potentially be allowed, provided they help answer my question.
So I've spent quite a bit of time scouring for sources on the Achaemid Dynasty in Persia, and Egypt, but my efforts have been fruitless.
So my question for you, /r/AskHistorians, is whether or not any of you know where I'd be able to find such sources in translation? I feel that I can do a decent amount of digging and find at least a few things that would help me on Alexander's side, however with Egypt and the Middle East, I'm unsure of even where to begin.
With that said, I appreciate any insight you all can offer.
Start with Amèlie Kuhrt's collection of primary sources, The Persian Empire. It has mostly all of the primary sources for the Persian Empire, including the years just prior to Alexander's conquests, in English. For more historical context, I highly recommend Pierre Briant's From Cyrus to Alexander. Briant focuses on the Persian perspective, the proceedings of the Achaemenid court, and the Near Eastern cuneiform primary sources, balancing out the heavily Greek-oriented modern scholarship that focuses on the Greek and Roman Alexander historians.
A word of caution: the Near Eastern primary sources for this period are not straightforward. There is no equivalence to the history of Arrian or Diodorus for the Persian Empire. What we have instead are a number of royal inscriptions, astronomical texts from Babylon, countless receipts from temples and storehouses, and legal contracts from more local governments. An investigation of the motives of Darius III, for instance, is difficult. Just be weary of any secondary source that claims otherwise.
Dealing with primary and even secondary sources is quite a bit more tricky for the Achaemenids than it is for either Classical Greece or Alexander. Fortunately, however, it's been a burgeoning academic field for the past few decades, and an impressively large body of scholarly literature has built up, including collections of the known primary sources for that period.
The main resource that tends to get used is The Persian Empire: A Corpus of Sources from the Achaemenid Period by Amelie Kuhrt, which collects a huge number of Greek quotes about the Persians alongside what primary evidence we have for the Achaemenid state, which is not as shallow as one might fear.
Just as a general guideline, there are three main sets of primary sources for the Achaemenids that come from the Empire itself- tablet-based documentation from Babylonia and Mesopotamia in general (which is generally very Babylonia-centric and mostly involves Mesopotamians), tablet-based documentation from Persia (almost all of it from Persepolis in collections like the Persepolis Fortification Tablets), and royal Achaemenid inscriptions like the famous one from Bishitun/Behistun (it has a lot of different transliterations...). That famous inscription tends to be the only royal inscription most non-Achaemenid focused scholars are familiar with, and thus it tends to attract inordinate attention. My advice is to not lean upon it as your primary primary source, so to speak.
The previous replies are good; I will only mention three additional smaller sources that might be of interest:
Aramaic ostraca, primarily from Judea. These apparently exist in considerable numbers and provide information outside of Babylonia.
Egyptian papyri. These are another rich source, but rich primarily as detailed administrative documents that tell us about how and why imperial government worked in Egypt.
The Bactrian Aramaic Parchments. This is probably one of the smaller sources; I mention it because unlike many if not most of our sources it reaches to the late Empire and to the period around Alexander's invasion(in fact one of the parchments is dated to a regnal year of Alexander) and it can tell us via a snapshot what imperial governance and administrative structure looked like in one relatively far-flung province.