The compass of accurate ...

The compass of  accurate knowledge directs the shortest, safest, cheapest course to any destination
The compass of accurate knowledge directs the shortest, safest, cheapest course to any destination
 Claude C. Hopkins

More phrases

All the great things are simple, and many can be expressed in a single word: freedom, justice, honor, duty, mercy, hope.
I know but one freedom and that is the freedom of the mind.
 Antoine de Saint-Exupéry
Freedom is not worth having if it does not connote freedom to err.
The amount of happiness that you have depends on the amount of freedom you have in your heart.
 Thích Nhất Hạnh
Without freedom of thought, there can be no such thing as wisdom - and no such thing as public liberty without freedom of speech.

Quotes from the same author

Ads are not written to entertain. When they do, those entertainment seekers rare little likely to be the people whom you want. This is one of the greatest advertising faults. Ad writers abandon their part. They forgot they are salesmen and try to be performers. Instead of sales, they seek applause
 Claude C. Hopkins
Literary qualifications have no more to do with it than oratory has with salesmanship. One must be able to express himself briefly, clearly, and convincingly, just as a salesman must.
 Claude C. Hopkins
The only readers we get are people whom our subject interests. No one reads ads for amusement, long or short... Give them enough to take action
 Claude C. Hopkins