In Pursuit of the Unknown

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In Pursuit of the Unknown
17 Equations That Changed the World
First edition (US)
AuthorIan Stewart
CountryUnited Kingdom
PublisherProfile Books (UK)
Basic Books (US)
Publication date
February 2012
Media typeHardcover
Preceded byCows in the Maze: And Other Mathematical Explorations (2010)[1] 
Followed bySymmetry: A Very Short Introduction (2013)[2] 

In Pursuit of the Unknown: 17 Equations That Changed the World is a 2012 nonfiction book by British mathematician Ian Stewart FRS CMath FIMA, published by Basic Books.[3] In the book Stewart traced a history of the role of mathematics in human history, beginning with the Pythagorean theorem (Pythagorean equation)[4] to the equation that transformed the twenty-first century financial market, the Black–Scholes model.


Seventeen equations are described in the book as follows:[5]

# Equation name Equation
1 Pythagorean theorem
2 Logarithms (logarithm product identity)
3 Calculus (definition of the derivative)
4 Newton's law of gravity
5 Square root of minus one
6 Euler's formula for polyhedra
7 Normal distribution
8 Wave equation (one dimensional)
9 Fourier transform
10 Navier–Stokes equations (for conservation of momentum)
11 Maxwell's equations (in vacuum, in Gaussian units)

12 Second law of thermodynamics
13 Relativity (Mass–energy equivalence)
14 Schrödinger equation
15 Information theory (Shannon entropy)
16 Chaos theory (logistic map)
17 Black–Scholes equation


Kirkus Reviews said that the book provided "clear, cogent explanations of how the equations work without burdening the reader with cumbersome derivations."[6]

The Maclean's magazine review described the book as a "history of the human species told in equations" by the "finest living math popularizer".[7]

The New York Book Review said that Stewart was a "genius in the way he conveys his excitement and sense of wonder across" who has a "valuable grasp" of "what it takes to make equations interesting" and "to make science cool."[8]

The Physics Today journal review said that Stewart writes with "easy prose, which never fails to both educate and entertain."[9]

Business Insider described the book as an "excellent and deeply researched book."[5]

The Association for Computing Machinery's SIGACT News review called the book, the "latest spell" by the "master storyteller", the "Honorary Wizard of the Unseen University"—the "master storyteller"—who is able to "entertain" the reader with Greek symbols.[10]: 11  The reviewer said Stewart focused on how equations have changed the world, as new equations gave "birth to new branches of science". Stewart provides the "historical background" to explain "how the equation was anticipated", how people then "generalized the ideas and formalized the results". He highlights the ways in which these equations continue to influence our lives in the twenty-first century.[10]: 11 

The review in Notices of the American Mathematical Society journal, described Stewart as an "experienced writer" whose intended audience is the "general literate reader"—not mathematicians. The reviewer, a mathematician, said that Stewart was "generally successful in getting the essential points across in a nontechnical way without too much distortion. However, he personally would have preferred a less "discursive style" but acknowledged that Stewart's writing was appropriate for his intended audience.[11]


"The Black–Scholes equation changed the world by creating a booming quadrillion-dollar industry; its generalisations, used unintelligently by a small coterie of bankers, changed the world again by contributing to a multitrillion-dollar financial crash whose ever more malign effects, now extending to entire national economics, are still being felt worldwide."

— In Pursuit of the Unknown 2012:310

In 17 Equations, Stewart described how the Black-Scholes equation provided the "mathematical justification for the trading"—and therefore—"one ingredient in a rich stew of financial irresponsibility, political ineptitude, perverse incentives and lax regulation" that contributed to the financial crisis of 2007–08.[12] He clarified that "the equation itself wasn't the real problem", but its abuse in the financial industry.[12]

See also[edit]


  1. ^ Stewart, Ian (2010). Cows in the Maze: And Other Mathematical Explorations. ISBN 978-0-19-956207-7.
  2. ^ Stewart, Ian (2013). Symmetry: A Very Short Introduction. ISBN 978-0-19965-198-6.
  3. ^ Stewart, Ian (2012). In Pursuit of the Unknown: 17 Equations That Changed the World. New York: Basic Books. p. 352. ISBN 978-1-84668-531-6.
  4. ^ Judith D. Sally; Paul Sally (2007). "Chapter 3: Pythagorean triples". Roots to research: a vertical development of mathematical problems. American Mathematical Society Bookstore. p. 63. ISBN 978-0-8218-4403-8.
  5. ^ a b Kiersz, Andy (31 March 2016). "The 17 equations that changed the world". Business Insider. Retrieved 29 April 2020.
  6. ^ In Pursuit of the Unknown. Retrieved 29 April 2020. {{cite book}}: |work= ignored (help)
  7. ^ Cosh, Colby (26 March 2012). "In Pursuit of the Unknown: 17 Equations That Changed the World". Maclean's. Review. Retrieved 29 April 2020.
  8. ^ "In Pursuit of the Unknown: 17 Equations That Changed the World". Review. 2012. Retrieved 29 April 2020.
  9. ^ Nahin, Paul J. (31 March 2012). "In Pursuit of the Unknown: 17 Equations That Changed the World". Physics Today. 65 (9): 52–53. doi:10.1063/PT.3.1720. ISSN 0031-9228.
  10. ^ a b Shehab, Omar (17 March 2014). "Review of in pursuit of the unknown: 17 equations that changed the world by Ian Stewart". ACM SIGACT News. 45 (1): 11–15. doi:10.1145/2596583.2596587. ISSN 0163-5700. S2CID 30631119.
  11. ^ Folland, Gerald B. (1 December 2012). "The Universe in Zero Words and in Pursuit of the Unknown–Review of Two Books". Notices of the American Mathematical Society. 59 (11): 1. doi:10.1090/noti924. ISSN 0002-9920. Retrieved 29 April 2020.
  12. ^ a b Stewart, Ian (12 February 2012). "The mathematical equation that caused the banks to crash". The Guardian. The Observer. ISSN 0029-7712. Retrieved 29 April 2020.