It's actually his personal diary, written often while he was on campaign. From that perspective I think it's impressive how insightful he managed to be in short

It's actually his personal diary, written often while he was on campaign. From that perspective I think it's impressive how insightful he managed to be in short bursts. But if you are looking for something more long-form, you might try Seneca's Letters or Epictetus Discourses.