question about Roman military writers

[Epictetus]

Some may have been lost. Augustus wrote memoirs, about which we know little. Claudius wrote histories of the Etruscans and Carthaginians. I think even Germanicus tried his hand at writing, but from what I remember one work was about astronomy. Although on the surface these works may not have been overly militaristic in nature, but how do we know all of the lost contents?

Edit: By the way, here's just a suggestion: you might consider having a more descriptive thread title. Someone with a good answer to this question might be browsing the forum and not bother to click on it to see what the topic is about.