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,

Since transacting at the right price is critical, trading is central to value-investment success. This does not mean that trading in and of itself is important; trading for its own sake is at best a distraction and at worst a costly digression from an intelligent and disciplined investment program. Investors must recognize that while over the long run investing is generally a positive-sum activity, on a day-to-day basis most transactions have zero-sum consequences. If a buyer receives a bargain, it is because the seller sold for too low a price. If a buyer overpays for a security, the beneficiary is the seller, who received a price greater than underlying business value.

The best investment opportunities arise when other investors act unwisely thereby creating rewards for those who act intelligently.