This book compiles the full, un-edited versions of every one of Warren Buffett's letters to the shareholders from 1965 to 2015, including 1965-1976 letters not available on Berkshire's website. In addition to providing an astounding case study on Berkshire's success, Buffett shows an incredible willingness to share his methods and act as a teacher to his many students.
There are hundreds of books about Buffett's life, advice, and methods. These are his actual letters -- word for word -- a "lesson plan" of his views on business and investing. You can find most of the letters for free on Berkshire's website, but this compiles them into a well-designed, easily readable format.