Sun Tzu Quote

Therefore I say: know the enemy and know yourself; in a hundred battles you will never be in peril. When you are ignorant of the enemy but know yourself, your chances of winning or losing are equal. If ignorant both of your enemy and of yourself, you are certain in every battle to be in peril.

The Art of War (ed. Wordsworth Editions, 1997) - ISBN: 9781853267796