Seth Klarman’s extraordinary and mysterious book Margin of Safety, Risk Averse Investing Strategies for the Thoughtful Investor has sold for $700 for used varieties with newer copies going for $2,500 to $4,000. His foremost investing premise is risk mitigation. He writes,

Many investors insist on affixing exact values to their investments, seeking precision in an imprecise world, but business value cannot be precisely determined. Reported book value, earnings, and cash flow are, after all, only the best guesses of accountants who follow a fairly strict set of standards and practices designed more to achieve conformity than to reflect economic value. Projected results are less precise still. You cannot appraise the value of your home to the nearest thousand dollars. Why would it be any easier to place a value on vast and complex businesses?

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Any attempt to value businesses with precision will yield values that are precisely inaccurate. The problem is that it is easy to confuse the capability to make precise forecasts with the ability to make accurate ones.