My highlights from the book: 

1. Don’t even think of temporary advantages. Don’t waste your effort on a thing which ends in a petty triumph unless you are satisfied with a life of petty success.

2. As our successes began to come, I seldom put my head upon the pillow at night without speaking a few words to myself in this wise: "Now a little success, soon you will fall down, soon you will be overthrown. Because you have got a start, you think you are quite a merchant; look out, or you will lose your head — go steady." These intimate conversations with myself had a great influence on my life. I was afraid I could not stand my prosperity and tried to teach myself not to get puffed up with any foolish notions.

3. We devoted ourselves exclusively to the oil business and its products. The company never went into outside ventures but kept to the enormous task of perfecting its own organization.

4. It has not been my custom to press my affairs forward into public gaze.

5. The only thing which is of lasting benefit to a man is that which he does for himself. Money which comes to him without effort on his part is seldom a benefit and often a curse.

6. I ascribe the success of the Standard Oil Company to its consistent policy of making the volume of its business large through the merit and cheapness of its products.

7. I have spoken of the necessity of being frank and honest with oneself about one’s own affairs. Many people assume that they can get away from the truth by avoiding thinking about it, but the natural law is inevitable, and the sooner it is recognized, the better.

8. Probably the greatest single obstacle to the progress and happiness of the American people lies in the willingness of so many men to invest their time and money in multiplying competitive industries instead of opening up new fields, and putting their money into lines of industry and development that are needed.

9. I know of nothing more despicable and pathetic than a man who devotes all the waking hours of the day to making money for money's sake.

10. It's a pity to get a man into a place in an argument where he is defending a position instead of considering the evidence. His calm judgment is apt to leave him, and his mind is for the time being closed, and only obstinacy remains.

11. It was a friendship founded on business, which Mr. Flagler used to say was a good deal better than a business founded on friendship, and my experience leads me to agree with him.

12. Perhaps they these stories will not be useless if even tiresome stories make young people realize how, above all other possessions, is the value of a friend in every department of life without any exception whatsoever.

13. Real efficiency in work comes from knowing your facts and building upon that sure foundation.

14. The novelty of being able to purchase anything one wants soon passes, because what people most seek cannot be bought with money.

15. This casual way of conducting affairs did not appeal to me.

16. You have to build a strong foundation for your business and for your life. And that takes time. If you do that correctly you're going to gain a level of efficiency that the people that are cutting corners are never going to enjoy.

17. We were gradually learning how to conduct a most difficult business.

18. Study diligently your capital requirements, and fortify yourself fully to cover possible set-backs, because you can absolutely count on meeting set-backs. Be sure that you are not deceiving yourself at any time about actual conditions. The man who starts out simply with the idea of getting rich won't succeed; you must have a larger ambition.

19. It is hardly necessary to caution a young man who reads so sober a book as this not to lose his head over a little success, or to grow impatient or discouraged by a little failure.

20. Perhaps it is worth while to emphasize again the fact that it is not merely capital and "plants" and the strictly material things which make up a business, but the character of the men behind these things, their personalities, and their abilities; these are the essentials to be reckoned with.