Edward O. Thorp: The Professor Who Beat Blackjack

Who was Edward O. Thorp? He is an American mathematician, born in Chicago on August 14, 1932, who showed in the early 1960s that blackjack could be beaten by keeping track of the cards already dealt. He published the result in a scientific paper in January 1961 and in the book Beat the Dealer in 1962. The Las Vegas Review-Journal has called that book the first widely published one with a proven system for card counting.

Thorp was a university mathematician, not a professional gambler, and his casino play was a research project that grew into a public sensation. Casinos barred him, rewrote the rules of blackjack in response to his book and then reversed course, while Thorp moved on to the stock market. This profile follows his story from a 1956 Army research paper to a Las Vegas card table, the 1964 rule change and the work that followed. It states plainly where sources disagree, and it describes his method only as history, never as instruction.

Blackjack Before Thorp

Blackjack, also called twenty-one, is a card game in which the player tries to get closer to 21 than the dealer without going over. According to the University of California, Irvine (UCI) exhibit on Thorp, single-deck blackjack was the standard in Nevada until the early 1960s.

The common belief was that no system could beat the house. Thorp himself told NPR’s Planet Money in 2017 that probability theory began with mathematicians studying how to win at gambling games and concluded that you cannot beat them. Games such as dice and roulette have no memory, because earlier throws and spins do not change the next one.

Blackjack was different in principle, because cards that have been dealt are out of the deck. A key early mathematical treatment came in September 1956, when Roger R. Baldwin and three co-authors, U.S. Army men working at Aberdeen Proving Ground, published “The Optimum Strategy in Blackjack” in the Journal of the American Statistical Association (volume 51, number 275, pages 429–439). Their paper told players when to stand and when to take a card, but it did not beat the game, according to the Review-Journal’s 2008 account. Thorp, then finishing his doctorate in mathematics at the University of California, Los Angeles, which he received in 1958, came across it that year.

From a Palm-Sized Card to an IBM 704

Thorp read the 1956 paper before a trip to Las Vegas in 1958, according to the UCI exhibit, which cites his 2017 memoir A Man for All Markets. He condensed its strategy onto a card small enough to hold in his palm and played blackjack for the first time. The Review-Journal notes that holding such a card at the table was not illegal at the time.

A seven-card 21 drew the attention of the table. Both the Review-Journal and NPR describe the hand: following the card, Thorp kept drawing until he held seven cards totaling 21. Thorp told NPR that the dealer had been ridiculing him and that the reaction changed afterward. He concluded that the casinos did not understand the game very well.

Back at UCLA, according to the NPR account, he reread the Army paper in the library and realized that as cards are used up the odds shift, sometimes favoring the casino and sometimes the player. The UCI exhibit quotes his memoir saying the earlier strategy assumed every card was as likely to be dealt as any other.

He moved to the Massachusetts Institute of Technology (MIT) in 1959. There, according to UCI, he used an IBM 704 computer to run through 34 million different ways the cards could be dealt. He concluded that with a bet limit of $500 the game could be beaten at the rate of $125 an hour. That was a projection, not a result. NPR reports that the calculating took him more than a year, and the memoir, as quoted by UCI, says he wrote to 26 Nevada casinos to learn how their rules varied and that 13 replied.

The 1961 Talk That Made Him Famous

In January 1961 Thorp did two things. He published “A Favorable Strategy for Twenty-One” in the Proceedings of the National Academy of Sciences, a journal that required an academy member to forward the work. According to UCI, that requirement led to his introduction to MIT mathematician Claude Shannon. He also presented his findings to the American Mathematical Society in Washington, D.C., in a talk titled “Fortune’s Formula: The Game of Blackjack.”

The talk created a public sensation. UCI’s exhibit quotes Thorp’s memoir saying that the national Associated Press wire service ran a story by Tom Wolfe, and that thousands of letters and phone calls poured into the MIT mathematics department. The Review-Journal puts the number of letters at 20,000. Thorp wrote that he had expected scholars to quietly agree with his work, not to be besieged by strangers.

One visitor, according to NPR, came on a February afternoon in 1961. Emmanuel Kimmel, who told Thorp he was a New York businessman, arrived at the apartment of the then 28-year-old mathematician and proposed to bankroll a trip to Nevada, wanting to start with $100,000. Two months later Thorp was at a blackjack table in Reno with thousands of dollars in chips. UCI’s exhibit quotes his memoir: “For me blackjack was a game of math, not luck.” In 1961 Thorp and Shannon also built what the Thorp papers’ finding aid describes as the first pocket-sized wearable computer, intended for roulette.

Beat the Dealer and the Casinos’ Response

Beat the Dealer was published in 1962, which the Review-Journal dates to November, and Thorp had written about his work in The Atlantic that June. The Thorp papers’ finding aid says the book became a New York Times bestseller and was the first to prove mathematically that the house advantage in blackjack could be overcome.

The casinos’ reaction was swift. As Thorp began to win and was recognized as the book’s author, he was repeatedly asked to leave casinos, the UCI exhibit says, noting that casinos are private clubs that can exclude whomever they please. Thorp experimented with disguises including contact lenses, sunglasses, a beard and changes of clothing and behavior. In his memoir he also recalled that dealers in that era sometimes dealt the second card instead of the top card to the player, a form of cheating he considered nearly impossible to prove. That claim rests on his own account.

The industry then acted. On April 1, 1964, according to UCI, the Nevada Resort Hotel Association announced that splitting pairs and doubling down would be restricted and that the deck would be reshuffled after just a couple of deals. A Denver Post headline dated March 30, 1964 reported a Nevada gaming chief disputing the professor’s system. The changes were unpopular with all players, people stopped playing blackjack, and the casinos reinstated the original rules, UCI says. Casinos also moved from single decks to shoes of four, six or eight decks, which Thorp wrote were not much harder to beat for counters using the High-Low system.

After Blackjack: The Stock Market and Recognition

The finding aid says that, after Beat the Dealer, it became hard for Thorp to enter a casino without being spotted and ejected, so he turned to investing with money from royalties and winnings. Working with UCI professor Sheen Kassouf, he developed hedged investment techniques, which led to Beat the Market in 1967. In 1969 Thorp and partner Jay Regan launched Princeton Newport Partners, which the finding aid calls the first market-neutral derivatives-based hedge fund.

Thorp taught at MIT from 1959 to 1961 and at New Mexico State University until 1965. He then became a founding faculty member at UCI, teaching mathematics from 1965 to 1977 and mathematics and finance from 1977 to 1982. In 2002 he was among the original seven members inducted into the Blackjack Hall of Fame, according to the same finding aid. He wrote six books in all.

Casino professionals also regard the book as having had lasting effects. The Review-Journal quoted a surveillance manager in 2008 saying the book still fundamentally influences how casinos monitor blackjack, and a security consultant calling Thorp the man who started it all.

Disputed Figures and the Other Side of the Story

Sources disagree on several points. Sales figures differ: the UCI exhibit says Beat the Dealer would sell over one million copies, while the Review-Journal reported in 2008 that Thorp calculated nearly 600,000. The 1964 rule change is dated precisely to April 1, 1964 by UCI, but the Review-Journal says only that casino owners met in early 1964 and adopted multiple-deck blackjack and fewer betting options.

The record also contains a corrective to the legend of easy money. Thorp told the Review-Journal in 2008, “I never did imagine I would make money at this,” and said the most he ever made playing blackjack was $11,000 in 20 hours at a Lake Tahoe casino during spring break from MIT. The $125 hourly figure in the UCI exhibit was a computer projection for a particular bet limit.

Counting was never a guarantee, and no source reviewed here presents it as a typical gambler’s path to profit. Thorp’s own account stresses disguises, bans and wary casinos. The cheating he described comes from his memoir alone, and no court record or official finding in the sources reviewed here confirms any specific claim.

Edward O. Thorp: Timeline

The key dates below come from the sources listed at the end of the article.

Related Stories on WagerPast

Thorp’s work touched games with very different histories. The mathematics of chance he applied to blackjack appears in a different form in the history of roulette, the game Thorp and Claude Shannon targeted with their wearable computer in 1961. The history of dice shows how long people have tried to understand random outcomes, and how little a die remembers about its last throw.

Thorp’s story is also one of gamblers using numbers to challenge the odds that bookmakers and casinos set. The history of the point spread follows another invention that changed how bets were priced, and the disputes about who deserves credit for it.

Sources & References

• UC Irvine Libraries — A Winning Hand (Edward O. Thorp exhibit)
• UC Irvine Libraries — Beat the House (Edward O. Thorp exhibit)
• Online Archive of California — Edward O. Thorp papers, 1946–2023 (UC Irvine Special Collections and Archives)
• Richard N. Velotta, Las Vegas Review-Journal — Counting a legend (February 25, 2008)
• NPR Planet Money — Episode 749: Professor Blackjack (January 20, 2017)
• Edward O. Thorp, The Atlantic — A Prof Beats the Gamblers (June 1962)
• Baldwin et al., Journal of the American Statistical Association — The Optimum Strategy in Blackjack (September 1956)
• Edward O. Thorp, A Man for All Markets (Random House, 2017), as quoted in the UC Irvine exhibit