There is nothing makes a man suspect much, more than to know little.

The life of spies is to know, not be known.

Guard more faithfully the secret which is confided to you than the money which is entrusted to your care.

Nothing is hidden from the eyes of the observing world.

To know all is not to forgive all. It is to despise everybody.

If you read somebody’s diary, you get what you deserve.

Spies are of no use nowadays. Their profession is over. The newspapers do their work instead.

Three may keep a secret, if two of them are dead.

I will never again command an army in America if we must carry along paid spies. I will banish myself to some foreign country first.

There is a sickness among tyrants: they cannot trust their friends.

Secrecy lies at the very core of power.

The first duty of a good inquisitor is to suspect especially those who seem sincere to him.

Secrets are rarely betrayed or discovered according to any program our fear has sketched out.