One of the recurring themes in Marcus' handbook is leadership's responsibility to work intelligently with what it is given and not waste time fantasizing about a world of flawless people and perfect choices.

Our wills are ours, to make them Thine.

Consider in what condition both in body and soul a man should be when he is overtaken by death; and consider the shortness of life, the boundless abyss of time past and future, the feebleness of all matter.

It is possible to depart from life at this moment. Have this thought in mind whenever you act, speak, or think.

If any man despises me, that is his problem. My only concern is not doing or saying anything deserving of contempt.

Always follow these two rules: first, act only on what your reasoning mind proposes for the good of humanity, and second, change your opinion if someone shows you it's wrong. This change of mind must proceed only from the conviction that it's both correct and for the common good, but not because it will give you pleasure and make you popular.

Cultivate these, then, for they are wholly within your power: sincerity and dignity; industriousness; and sobriety. Avoid grumbling, be frugal, considerate, and frank; be temperate in manner and speech; carry yourself with authority.