But big simple ideas like these are not easy to find amidst the suffocating mass of detail in Schroeder's book. Like many biographies, it starts off with something eye-catching and juicy before jumping back to ancestors and heritage; Schroeder decided that her centerpiece for Part One of the book would be a scene at Sun Valley in 1999 where Buffett confronted the tech titans with their bubblicious stocks.

Buffett's talk at Sun Valley was quite simple. He said, basically, that tech stocks were overpriced. Many other people were saying that, too, and most people, even at Sun Valley, knew it, in their hearts, to be true. Why did Schroeder decide to lead with this talk, rather than any of Buffett's decisions in and around his life's great achievement, Berkshire Hathaway? It's far from clear. And it's a most frustrating chapter to read, too: because you never know quite why Schroeder is leading with this, or that the whole point of the chapter is nothing but a speech, you keep on picking up on detail which sounds like foreshadowing but isn't.

Why, for instance, does Schroeder spend the first two pages of the chapter talking about Buffett's flight in to Sun Valley? How can you read a passage like this and not think that it's serving some kind of purpose?

Sometime later, the G-IV crossed the Snake River Plain and approached the Sawtooth Mountains, a vast Cretaceous upheaval of dark and ancient granite mounds baking in the summer sun. It sailed through the bright clear air into the Wood River Valley, descending to eight thousand feet, where it started to buck on the mountain wave of turbulence thrown into the sky by the brown foothills beneath. Buffett read on, unperturbed, as the plane rocked and his family jerked about in their seats...

I was convinced we were about to have a bloody plane crash; instead, the plane is uneventfully met at the airport by Herb Allen's Sun Valley minions, and nothing is ever heard about it again. The same thing happens when Schroeder starts talking pointedly about the "very, very attractive" babysitters laid on by Allen—but again, nothing comes of it. All we get is a speech, decorated by flowers which, Schroeder says, Buffett doesn't even notice: "scarlet petunias and blue sage"; "pastel lupines and sapphire delphiniums towering over poppies and Indian paintbrush, crisp blue salvia and veronica nestled among the stonecrop and hens-and-chicks."

In other words, this is a book which doesn't just make it hard to make out the forest for the trees; it makes it hard to make out the trees for the texture of their bark and the exact shape and number of their branches.

I have no idea why Schroeder felt the need to lard the book with so much pointless detail, but if the first two parts of the book are any indication, it might be because she's so hesitant about inserting her own analysis or ideas about the bigger picture.

In general I'm a fan of the show-don't-tell school of writing, but this is a very smart woman who has spent five years intimately involved with Buffett, his friends, his family, and his business partners. We could be forgiven for wanting to know what she thinks of him.

Yet for a woman who's happy to spend two pages on a completely irrelevant plane journey, Schroeder seems to be very good at completely missing some of the big issues. For instance, Buffett had one thing in common with the technology gurus to whom he gave his speech at Sun Valley, and which he doesn't have in common with the founders of most other companies: he never pays dividends.

This decision makes valuing Berkshire Hathaway stock more difficult than it needs to be. Remember that according to financial theory, the value of a stock is just the net present value of all future dividends.

While tech companies that don't pay dividends are very common, industrial companies with strong cash flows and strong profits almost always pay dividends. Berkshire Hathaway, which has only ever paid one dividend in its entire existence—10 cents, in 1967—is far the biggest exception, and yet Schroeder doesn't seem to spend much time exploring this issue.

Buffett's no-dividends decision means that anybody who's made a lot of money from investing in Berkshire Hathaway stock falls into one of two camps. Either they sold their stock—a betrayal of everything Buffett stands for—or else they're sitting only on paper gains. And remember that Buffett's most cherished shareholders are the ones holding one or two or maybe three A shares worth well over $100,000 apiece. They can't sell 3 percent of their stockholding to get a little income: that's a necessary consequence of having shares with such enormous face value.