The third principle is to lead by example. There is no such thing as a fine army with a bad leader. The army will deteriorate to the level of its guide.
Which one, you ask? We'll just go with one for the moment.
"Does this dress make me look fat?" At this point, alarm bells should be ringing in your head. Just in time, a bit of wisdom flashes through your head. "If weaker, be able to avoid them..."
You drop whatever you are doing, and sprint away in a speedy retreat. Disaster successfully averted!
Perhaps that situation was a bit exaggerated. But I'm sure you can see how this would come in handy. ;)
GENRE: Non-fiction, Classic, War History.
(Short, but pithy, and a good read)
Obviously, this isn't the most entertaining read on the planet. It's a military treatise. However, it is so good for its purpose, that it is still read today at West Point.
(Not a ton of content here. I wouldn't recommend it to children, seeing as the purpose is to provide guidance on how to annihilate opposing armies, and several non-graphic examples are provided.)