Most of the letters are freely available on Berkshire's website. The "extra material" includes a few early letters not on the web (got these from Buffett so the

Most of the letters are freely available on Berkshire's website. The "extra material" includes a few early letters not on the web (got these from Buffett so the collection would be complete), and charts/tables/indexes that I put together myself. The income is not shared with Buffett, but any income I receive is "return on capital" from me taking inventory risk. So I do have to invest some of my $$$ to buy the book inventory, and as it's sold to Amazon I make (great) return on that money. But the profit per book is actually pretty low compared to other published books -- I could be charging much more for the book, but it was part of our "agreement" that I make the total price of the book as cheap as possible. (Which I think is accomplished with Amazon's price of $19-25 for a 700 page textbook-size book.)