Me and my friend are doing our final high school paper (PWS for the dutchmen) on why Alexander the Great's generals remained faithful to him during his conquest in the east from 333 B.C. to 326 B.C. Because after Alexander's death they declared war on each other and only cared about themselves.
We've read the main sources on Alexander's life (Plutarch's Parallel lives and Arrian's anabasis). We have also found some great secondary (technically tertiary) sources on Alexander the Great's life and conquest. But we've found surprisingly few on the general's personalities. Most books, including Plutarch and Arrian, zoom in on Alexander (which makes sense). And while that's super interesting, we really need some detailed info on the personality of the generals.
There are some books about famous generals like Ptolemy, Seleucus and Cassander. But what about all the other generals? From Alexander's experiences we can only guess what kind of persons they were, but we would really like some facts.
If you guys even know one source, you would really help us out.
I can't really help you much in terms of primary sources on the Diadokhoi, but I can recommend two good books that came out relatively recently (and, coincidentally, at almost the same exact time). Ghost on the Throne: The Death of Alexander the Great and the Bloody Fight For His Empire by James Romm is one, and Dividing the Spoils: The War for Alexander the Great's Empire by Robin Waterfield is the other.
Of the two, the Waterfield book is probably the more "scholarly," although they're both written with a popular audience in mind. Waterfield also covers the entirety of the wars of the Diadokhoi, beginning with Alexander's death in 323 BC and ending with the death of Seleucus in 281 BC. Romm, on the other hand, focuses more on the immediate military campaigns fought by the Successors and only goes up to the end of the 4th century. However, both books should serve you well.