Value investing is an investment paradigm that derives from the ideas on investment and speculation laid forth by Ben Graham & David Dodd in their 1934 text Security Analysis. Although value investing has taken many forms since its inception, it generally involves buying securities whose shares appear underpriced by some form(s) of fundamental analysis. The discount of the market price to the intrinsic value is what Benjamin Graham called the "margin of safety". The intrinsic value is the discounted value of all future distributions.
However, the future distributions and the appropriate discount rate can only be assumptions. Warren Buffett has taken the value investing concept even further as his thinking has evolved to where for the last 25 years or so his focus has been on "finding an outstanding company at a sensible price" rather than generic companies at a bargain price, this concept is important as you are actually buying into a business.

History
Value investing was established by Benjamin Graham and David Dodd, both professors at Columbia University and teachers of many famous investors. In Graham's book The Intelligent Investor, he advocated the important concept of margin of safety — first introduced in Security Analysis, a 1934 book he coauthored with David Dodd — which calls for a cautious approach to investing. In terms of picking stocks, he recommended defensive investment in stocks trading below their tangible book value as a safeguard to adverse future developments often encountered in the stock market.

Benjamin Graham
However, the concept of value (as well as "book value") has evolved significantly since the 1970s. Book value is most useful in industries where most assets are tangible. Intangible assets such as patents, software, brands, or goodwill are difficult to quantify, and may not survive the break-up of a company. When an industry is going through fast technological advancements, the value of its assets is not easily estimated. Sometimes, the production power of an asset can be significantly reduced due to competitive disruptive innovation and therefore its value can suffer permanent impairment. One good example of decreasing asset value is a personal computer. An example of where book value does not mean much is the service and retail sectors. One modern model of calculating value is the discounted cash flow model (DCF). The value of an asset is the sum of its future cash flows, discounted back to the present.

Further evolution

Performance, value strategies
Another way to examine the performance of value investing strategies is to examine the investing performance of well-known value investors. Simply examining the performance of the best known value investors would not be instructive, because investors do not become well known unless they are successful. This introduces a selection bias. A better way to investigate the performance of a group of value investors was suggested by Warren Buffett, in his May 17, 1984 speech that was published as The Superinvestors of Graham-and-Doddsville. In this speech, Buffett examined the performance of those investors who worked at Graham-Newman Corporation and were thus most influenced by Benjamin Graham. Buffett's conclusion is identical to that of the academic research on simple value investing strategies--value investing is, on average, successful in the long run.
During about a 25-year period (1965-90), published research and articles in leading journals of the value ilk were few. Warren Buffett once commented, "You couldn't advance in a finance department in this country unless you thought that the world was flat."

Performance, value investors
Benjamin Graham is regarded by many to be the father of value investing. Along with David Dodd, he wrote Security Analysis, first published in 1934. The most lasting contribution of this book to the field of security analysis was to emphasize the quantifiable aspects of security analysis (such as the evaluations of earnings and book value) while minimizing the importance of more qualitative factors such as the quality of a company's management. Graham later wrote The Intelligent Investor, a book that brought value investing to individual investors. Aside from Buffett, many of Graham's other students, such as William J. Ruane, Irving Kahn and Charles Brandes have gone on to become successful investors in their own right.
Graham's most famous student, however, was Warren Buffett, who ran successful investing partnerships before closing them in 1969 to focus on running Berkshire Hathaway. Charlie Munger joined Buffett at Berkshire Hathaway in the 1970s and has since worked as Vice Chairman of the company. Buffett has credited Munger with encouraging him to focus on long-term sustainable growth rather than on simply the valuation of current cash flows or assets.
Another famous value investor is John Templeton. He first achieved investing success by buying shares of a number of companies in the aftermath of the stock market crash of 1929.
Martin J. Whitman is another well-regarded value investor. His approach is called safe-and-cheap, which was hitherto referred to as financial-integrity approach. Martin Whitman focuses on acquiring common shares of companies with extremely strong financial position at a price reflecting meaningful discount to the estimated NAV of the company concerned. Martin Whitman believes it is ill-advised for investors to pay much attention to the trend of macro-factors (like employment, movement of interest rate, GDP, etc.) not so much because they are not important as because attempts to predict their movement are almost always futile. Martin Whitman's letters to shareholders of his Third Avenue Value Fund (TAVF) are considered valuable resources "for investors to pirate good ideas" by another famous investor Joel Greenblatt in his book on special-situation investment "You Can Be a Stock Market Genius" (ISBN 0-684-84007-3)(pp 247)
Joel Greenblatt achieved annual returns at the hedge fund Gotham Capital of over 50% per year for 10 years from 1985 to 1995 before closing the fund and returning his investors' money. He is known for investing in special situations such as spin-offs, mergers, and divestitures. Edward Lampert is the chief of ESL Investments. He is best known for buying large stakes in Sears and Kmart and then merging the two companies.
Well Known Value Investors

See also

Warren Buffett
Benjamin Graham
Joel Greenblatt