Others have dealt with the specifics and offer many quotes from Cunningham's book. I will deal with why you need to read this book, and its source material directly.
Warren Buffett has never written a book, which is sad for the rest of us, and he probably never will. At the same time, Buffett is one of the finest writers on financial thought in our society today. The clarity, brevity, perfect phrasing, and play on words that he is capable of, would lead most sophisticated readers to believe that the Sage of Omaha could have had quite a remarkable career in journalism had he chose to go another way in life.
Since 1977, what Buffett has done so effectively, is personally write (no committees, or public relations firms) a Chairman's letter to his Berkshire Hathaway shareholders. The letters (all of them) are freely available to you by going to the Berkshire website, and downloading them. The earliest letters were much shorter than the later letters, as Buffett's style writing style evolved. He was also more willing to share his thoughts in later years.
Lawrence Cunningham, the editor of these essays is a very fine financial mind in his own right. What he has done is organize the contents of the Buffett letters into different categories. At the same time, he has left out the technical aspects of the letters for the most part, which refers to any specific transactions Berkshire committed in any given year. This allows us, the readers to be able to go right for the wisdom that is contained in the letters. We are thus able to leap over what some readers might consider less important financial details of business transactions.
IS THIS THE WAY TO GO?
For many it is better to read Cunningham's book. The choice reminds me of the joke about the two lecture halls at Harvard University. One says GOD on the door. The other says LECTURE ON GOD. Everybody wants to go to the LECTURE as opposed to seeing the real thing. In this case the real thing is Buffett's words without someone organizing them for you.
All communication is context related. You know this. If you were to download the letters, one at a time, and read them in chronological order starting with the first letter, something quite remarkable might happen.
You would be getting the PURE FLOW of Buffett's mind, from him to you directly - NO INTERMEDIARIES. Yes, depending upon your sophistication, you might not understand everything he is saying, but that doesn't matter. You'd get it, I promise you.
You'd write in the margins as I do. You would underline, or highlight what is important. You would write questions. You'd make those letters yours; in short, you would take OWNERSHIP OF THEM. At the end of your journey, you would have an extraordinary financial education.
You would learn things that you will never ever read anywhere else. This is because you would be the one interpreting Buffett , and you would have startling insights that other writers have not picked up on. Just about everybody writing about Buffett from authors, to journalists are not in the same league as the MASTER. They want to impress you themselves with their words, and their ideas, or twist Buffett's thinking and bask in the reflected glory. Please allow me to illustrate.
Nobody ever writes about how Buffett is hardwired in a different way than the rest of us, and this is his genius. It's no different than running into Newton, Einstein, or Leonardo da Vinci. The concept of compounding on a geometric level is in Buffett's brain while the rest of us play at an arithmetic level. This is no different than a World Champion Chess Master. The only difference between an International Grand Master (IGM), and a World Champion is that the World Champion can think one more move ahead than the IGM.
In a meeting I attended in Wall Street a couple of decades ago, Buffett said, "One of the stupidest things you can do with money is spend it." Who else on the planet would say such a thing? He meant it too. Buffett doesn't think like an investor, he thinks like a businessman who is making investments, only when he makes them, they are not investments to him. They are allocations of capital. You will notice he is always talking about allocations of capital. So what does this mean?
If you can get a 20% yearly compounded rate of return for decades with no tax consequences until you sell (capital gains treatment in the end), you can build capital into the billions depending upon what you start with. Take Emerson a company you probably don't know. A dollar invested in 1956, by 2000 was worth $638. Those are Buffett type returns, and I can show you scores of public corporations that are comparable in performance. You must hold long enough to let compounding work for you.
BOOK is FABULOUS
You want to read this book for the wisdom, the quotes, that you can memorize, and attempt to exploit for your personal investment advantage. We should all be grateful to the author for doing this. Buffett himself has publicly complimented the author for his work because he is the first author to give you pure Buffett without altering the Master's words.
In closing, I have read Cunningham's book several times, and you should too. Just don't forget to go to the actual source documents, the letters themselves. Carry one around with you in your pocket, and just read it in a park, in a restaurant, or anywhere else you can reflect, and work with pure genius.