Wit and Wisdom from Poor Richard's Almanac

is an excellent book by Benjamin Franklin (isbn 0-486-40891-4). As usual I'm going to quote from a few pages:
Observe all men; thyself most.
At 20 years of age the Will reigns; at 30 the Wit; at 40 the Judgement.
Laziness travels so slowly that Poverty soon overtakes him.
He that never eats too much will never be lazy.
He that resolves to mend hereafter, resolve not to mend now.
Friendship cannot live with Ceremony, nor without Civility.
Men take more pains to mask than mend. Bad Gains are truly Losses.
A good wife and Health, is a Man's best Wealth.
Buy what thou hast no need of, and e'er long thou shalt sell they necessaries.
He that would catch Fish, must venture his Bait.
Learn to be skilful; He that teaches himself, hath a fool for his master.
Tis easier to suppress the first Desire, than to satisfy all that follow it.
He that would live in peace and at ease, Must not speak all he knows nor judge all he sees.
He that cannot obey, cannot command.