The richest investors — not to mention the most talented — have forged new paths in the stock market, innovated with mutual funds or blown open the gates with bonds. Through their innovations, bold risk-taking and deep wells of experience, they've left those who follow in their footsteps with the most valuable asset of all: education.

Take it from one of America's earliest financial path-forgers, Benjamin Franklin, who's attributed with the saying "an investment in knowledge pays the best interest." The best part is, your investment is free: Just sit back and learn how it's done from these 15 investment icons.

Starting this list with Warren Buffett, who currently sports a net worth of about $85 billion, should surprise no one. Buffett bought his first stock at the age of 11. Nowadays his company, Berkshire Hathaway, owns more than five dozen companies, from Duracell and Geico to Dairy Queen. Buffett has given almost $32 billion of his investing-based fortune to charitable causes and plans to give much more.

Buffett's investment strategy, called value investing, is pretty simple. It involves grabbing stocks that are underpriced relative to their peers based on a price-to-earnings ratio. At its most basic level, Buffett advises investors to start cheap, be patient and wait for big returns.

Munger, vice chairman at Berkshire Hathaway, does things a little differently than his more famous colleague. Munger has gone on record calling value investing a collection of "cigar-butt stocks" that can be "a snare and a delusion." His preferred strategy is equally simple, though: Invest in high-quality companies with a product or service you believe in.

During a 2016 Daily Journal shareholder meeting, Munger said a 1962 investment in oil royalties was one of his best. At the time, he put up $1,000 to buy oil royalties at auction. The result? The Munger family raked in about $100,000 a year for roughly 50 years.

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Rounding out the Buffett trifecta is the man who served as a mentor to Buffett and Munger. In fact, Benjamin Graham is the person responsible for cooking up the value investment strategy.

The "Father of Modern Investing" took his experiences living through the Great Depression and turned them into what he called safe, "intelligent investing." From 1936 to 1956, Graham's investment firm generated annual returns of about 20 percent compared to average market returns of roughly 12 percent at the time. Before passing away in 1976, Graham published the classic manual, "The Intelligent Investor." It's a great book for beginning investors to read.

Known as the "Queen of Blue-Chip Dividends," Geraldine Weiss was also mentored by Graham by way of his books — at least until she developed her very own trailblazing strategy.

Weiss propagated the notion of picking stocks based on dividend yield, which entails buying stocks near their highest historic dividend yield and selling them near their lowest historic dividend yield. She popularized this strategy in the newsletter she founded in 1966, "Investment Quality Trends." Since 2000, IQT's "Lucky 13" list has recommended a portfolio that has boasted returns more than twice that of the S&P 500.

Peter Lynch's streak with the Fidelity Magellan Fund from 1977 to 1990 is the stuff of legend. Under his leadership, the fund generated a total return of 2,510 percent, or five times the return of the S&P 500 at the time. It's little wonder the Wall Street Journal dubbed Lynch a "mutual-fund rock star."

Lynch authored bestsellers like "Beating the Street" and "One Up on Wall Street: How to Use What You Already Know to Make Money in the Market." He encouraged investors to buy what you know because while "big companies have small moves, small companies have big moves," as he wrote in "One Up on Wall Street." By investing in small-cap businesses that grew organically over years, Lynch generated a 29.2 percent annual return for 13 years.

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Speaking of streaks, Bill Miller rose to fame by beating the market for 15 straight years at asset management firm Legg Mason from 1991 to 2005. In May 2017, his Opportunity Trust mutual fund was up 13.9 percent compared with the S&P 500's 7.8 percent gain.

Opportunity Trust's strong performance is partly attributable to Buffett-like value investing. Though overexposure and illiquid investments during the Great Recession were a low period for Miller, a 2017 comeback was mostly owed to long-held stock in Apple, a long-term value investment that rocketed up by 32 percent during the first half of 2017.

The son of a finance minister, Saudi Arabian Prince Alwaleed Bin Talal is valued at about $17 billion. His portfolio at Kingdom Holding Co. emphasizes diversity and globalization, featuring stakes in names like Lyft, Citigroup, Twitter and Four Seasons Hotels & Resorts. Alwaleed also invests heavily in real estate and entertainment and holds a majority stake in Rotana Group, an Arabic-language entertainment firm.

In late 2017, Saudi Arabian authorities detained Alwaleed as part of a nationwide anti-corruption purge, demanding $6 billion for his release. So wide-ranging are his investments in major Western companies that Alwaleed's detention, as Reuters put it, "could have an impact on billions of dollars of investments around the world."

A Saudi Arabian financial powerhouse on the more progressive side of the spectrum, Lubna Olayan has been breaking glass ceilings since 1983, when she became the first woman to go to work for her father's business, Olayan Financing Co. Lubna Olayan is now CEO of the company and principal of its parent, Olayan Investments Company Establishment. She also serves as vice chairman at Saudi Hollandi Bank, director at Schlumberger Ltd. and advisor at the Council on Foreign Relations, Rolls Royce Holdings and Akbank, among others.

Olayan, who has made historic strides in employing Saudi Arabian women, never limits her business opportunities to a single category. Olayan Financing has its hands in stocks, real estate and manufacturing. The company owes much of its success to partnerships and joint ventures, helping bring major international brands such as Burger King, Colgate Palmolive, Nabisco and Xerox to the Middle East. No matter the size and scale of your investments, it's always good to diversify your holdings.

No one did long-term investing like Phil Fisher, who founded the money management firm Fisher & Co. in 1931 and authored the enduring "Common Stocks and Uncommon Profits." One of the first investors in Texas Instruments, Fisher didn't live to see that company's market capitalization explode to over $40 billion. TI is still a great investment choice today.

Perhaps no single stock reflects Fisher's philosophy as well as his investment in Motorola, which he purchased in 1955, about 40 years before anyone knew what a cell phone was. He held the stock until his death in 2004. As you might have guessed, Fisher was a proponent of finding the best growth stocks, investing early and holding onto a concentrated, high-quality portfolio for decades. He called this approach investing in "statistical bargains."

David Einhorn not only ranks as one of Forbes' 25 highest-earning hedge-fund managers and traders in the world, he's a case study in bouncing back from mistakes. After a record slump in 2016, his Greenlight Capital hedge fund boasted an 8.4 percent gain in 2017. Strategy-wise, that bounce is owed to Einhorn's reputation as a short seller.

Though Einhorn has historically subscribed to the value investing theory, he believes in evolving with the ever-changing market. In a 2017 investor letter he wrote, "What if equity value has nothing to do with current or future profits and instead is derived from a company's ability to be disruptive [...] even when doing so results in [...] economic loss?" He cites major disruptors like Amazon and Tesla, whose soaring stocks don't always reflect their financial results.

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Bond king Bill Gross made his stamp on the financial world as co-founder of investment management firm PIMCO in 1971. It is now one of the largest mutual funds in the world. For a time, this made Gross the planet's biggest bond fund manager, peaking at $293 billion worth of funds at PIMCO in 2013.

PIMCO plummeted after Gross departed for Janus Capital Group in 2014, where he continues to rail against the trend of "making money with money" in favor of "capital investment in the real economy." Gross encourages investors to avoid the short-sighted trap of investing in what he calls "zombie corporations." These investments you can feel good about ethically and financially.

When he passed away in 2008, John Templeton had become synonymous not only with investment but with philanthropy. A product of the Great Depression and graduate of Yale University, Templeton went to work on Wall Street in 1938. He quickly developed a strategy of buying low and selling high in which he scooped up rock-bottom stocks at "points of maximum pessimism." In 1939 Templeton borrowed money to buy 100 shares each of 104 companies that sold for $1 per share or less. He wound up realizing large profits on all but four of those companies.

Any $10,000 invested in his Templeton Growth Fund in 1954 had grown to $2 million by 1992. It's little wonder that Money magazine once called Templeton "arguably the greatest global stock picker of the century." He also became known for his philanthropic efforts, including the Templeton Foundation and annual Templeton Prize.

Hedge-fund manager George Soros has an estimated net worth of around $8 billion, which is especially impressive considering where he came from. Born in Hungary, he fled the Nazi-occupied country as a young man and paid his own way through the London School of Economics, working double-time as a waiter and railway porter. Today, his Soros Fund Management handles $26 billion in assets while his philanthropic Open Society Foundations have expenditures of nearly $14 billion.

In 1992, Soros earned $1 billion in a single day by making a massively risky bet against the British pound. Over the course of four decades, his investments compounded at a rate of 26.3 percent. That means if Soros made an investment of $10,000 in 1969, it was worth $143.7 million in 2009. Soros came up with the theory of reflexivity, a strategy that depends on markets constantly diverging from investors' perceptions of reality.

In 1967 Muriel Siebert became the first woman to own a seat on the New York Stock Exchange. This was before she went on to become one of Wall Street's richest stockbrokers. Though Siebert passed away in 2013, Muriel Siebert & Co. remains the only nationally known brokerage headed by a woman, now majority owned by Gloria E. Gebbia.

Breaking gender barriers weren't all Siebert was good at, though. A truly innovative investor, she dropped out of school in 1954 and headed to New York with only $500. In addition to Siebert's constant stream of steady returns in the '60s and '70s, her firm was one of the first to offer discounted rates after the SEC allowed negotiable broker commissions in 1975. She became the highest-ranking female regulator in history when she stepped up as New York State's Superintendent of Banks in 1977. She also founded and presided over the New York Women's Forum, which is active to this day.

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David Swensen made his mark in finance by synthesizing portfolio management and education. As Yale's endowment manager, he is in charge of more than $27 billion in assets plus hundreds of millions in other investments. After working throughout the 1980s developing financial technologies for Wall Street, Swensen became a modern legend among endowment managers. By 2016 he and his stable of Yale proteges were responsible for more than $100 billion in endowment funds across schools such as M.I.T., Stanford and Princeton. As detailed in his book, "Pioneering Portfolio Management," Swensen preaches moving away from the traditionally conservative stocks-and-bonds-based investment strategies in favor of the broader horizons of real estate, private equity and venture capital.

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