Not so long ago, investing used to be fun. Now it resembles an Olympic archery practice at which the target is you. Maybe you felt a little safer this Thursday, when the Dow went up 553 points. Well, today it dipped by as much as 352 before closing down 338 points.

If you want to escape the arrows, you can find some refuge by reading the new biography by Alice Schroeder, The Snowball: Warren Buffett and the Business of Life (published by Bantam on Sept. 29, the day Congress voted down the first bailout plan and the Dow fell almost 800 points). Although he is lucky in many ways, Mr. Buffett is also the world’s most successful investor because he has worked extraordinarily hard and thought very deeply about his craft.

Mr. Buffett gave Ms. Schroeder thousands of hours of face time, a privilege earlier biographers did not have. In 1995, Roger Loewenstein’s superb book Buffett: The Making of an American Capitalist analyzed Mr. Buffett’s rationale for specific investments in illuminating detail, but Ms. Schroeder has been able to delve more deeply into Mr. Buffett’s mind and heart.

The result is riveting and encyclopedic. At 960 pages and 3½ lbs., The Snowball hits readers like an avalanche. Some people feel almost buried by the wealth of detail about Mr. Buffett’s family life, but the overall power of the story carries The Snowball forward. There is much to be learned from it.

To me, the most striking thing to come out of the book is a clearer sense of Mr. Buffett’s extraordinary emotional detachment. Remember, this is an authorized biography; as Mr. Buffett’s spokesperson put it, “She [Ms. Schroeder] wrote every word, and he did not edit it.”

After years of emotional isolation from the workaholic Mr. Buffett, his wife Susie “stayed up late at night alone, listening to music that transported her to some different place…. She loved…great soul music, like the Temptations, who sang of a world in which it was men who felt all the longing.”

Passages like these are heartbreaking for even a stranger to read. How many of us could bear to let someone else bare our most intimate weaknesses and failures? And yet here we not only see the pain that Mr. Buffett caused his wife, but we know that he has acquiesced in letting us see it.

This detachment, I think, is one of Mr. Buffett’s greatest strengths. He has the ability to hover over his own actions and judgments, as if he were having an out-of-body experience, looking down and evaluating the man who made them as if he were someone else entirely.

In person, Mr. Buffett is as warm and empathetic a person as anyone I have ever met — but he also seems, in Ms. Schroeder’s telling, to be forever observing himself from a distance as well. There is, in her portrait of him, a streak of something at least mildly reminiscent of autism: a photographic memory, an effortless command of complex mental computations, an enduring obsession with collecting and measuring everything imaginable.

This almost-autistic streak in Mr. Buffett exacted a terrible toll on his family as he toiled around the clock for years. Long before it was common, he worked out of a home office, and it is hard to shake the image of him padding through the house in his stocking feet, his face buried in an annual report, oblivious to his own family.

Mr. Buffett’s unparalleled record of investing achievement came at a personal price most of us would never be willing to pay; although he now has a warm relationship with his adult children, his billions were earned only at an incalculable emotional cost in their earlier years.

I shuddered several times as I read Ms. Schroeder’s account of how desperate Mr. Buffett’s family was for his affection. Anyone who thinks beating the market is easy should think twice, based on Mr. Buffett’s own experience.

The Schroeder book makes it clear that in his early years, Mr. Buffett paid a toll so high, in currency so dear, that most investors would not dare to approach the same tollbooth.

Here are the investing ideas that I think the book highlights in new detail:

Discipline. What explains Mr. Buffett’s success? His one-word answer: “focus.” For him, that meant working all hours day and night, memorizing oceans of statistics about hundreds of stocks, and reading corporate financial statements on a family trip to

Mr. Buffett’s uncanny ability to stay one step ahead of the markets comes from five decades of working harder on his homework than anyone else. Can you even name the three toughest competitors of every company whose stock you own?

Self-confidence. From his father, an iconoclastic politician, Mr. Buffett inherited what he calls the knack of keeping an “inner scorecard,” rather than an “outer scorecard.” He does not care whether other people agree with him. He cares only whether his decisions make sense to him, based on his own rigorous research. Do you invest based on what “everybody knows” is “true,” or do you analyze all the evidence yourself?

Self-control. Mr. Buffett does not let the emotions of millions of strangers — the collective greed and fear of the markets — determine his own mood. When he feels his blood pressure rising or his nerves on edge, he calms himself down by gazing at snapshots of his kids or playing a game of bridge with his friends. Mr. Buffett restores his sense of self-control by refusing to dwell on the things he cannot control. Are you staring at every scarlet downtick on the Dow?

Inversion. Mr. Buffett most likes to buy stocks not when they are going up, but when they are going down. In 1969, during a raging bull market, he shut down his original investment partnership. Then, in 1974, when stocks (and market sentiment) hit rock bottom, Mr. Buffett bought with such abandon that he felt “like an oversexed guy in a harem.” Again, in 1999, as investors went gaga for technology stocks, Mr. Buffett sat on his hands. In the miserable market of 2008, he is buying again (although sometimes on “sweetheart” terms not available to you and me). Are you tempted to stand aside from stocks until after they go up?

The long view. From a very young age, Mr. Buffett developed the remarkable habit of regarding a dollar spent today as a small fortune he would not have in the future: “Do I really want to spend $300,000 for this haircut?” He felt that any money he could not invest was money that would never grow — and that he would thus incur a huge future price for any present spending. If you are among the many people cutting back your 401(k) contributions because the market has cratered, have you thought about the cumulative future costs of that decision?

Rigid versatility. Throughout his career, Mr. Buffett has been tactically flexible but strategically inflexible. His core principles have never varied one iota: Buy only what he understands, never overpay, always put safety first, be patient. But Mr. Buffett is as stretchy as Plastic Man when it comes to implementation. He will buy silver ingots, or municipal bonds, or a privately held company that manufactures both bricks and cowboy boots — whatever is on sale at the right terms. Now that virtually every investment on earth is down between 10% and 60%, is cash the only thing that interests you?