Who's Who

The people behind the ideas.

Historic and current figures in calculus — what they contributed, and why it still lands in a classroom today. Every entry says what the person actually did, not just that they were important.

The first twenty-five

1643–1727 · England

Isaac Newton

Newton set calculus in motion — literally. Working in the 1660s and 1670s he developed what he called the “method of fluxions”: rates of change and the inverse problem of recovering a quantity from its rate. He then used it as the engine of the Principia (1687), deriving planetary motion and gravity. His bitter priority dispute with Leibniz split European mathematics for a century.

Why it lands in class: Newton is the answer to “why do we care about rates?” Velocity, acceleration and force are the intuition students already have; the derivative is the machinery that makes it precise.

Further reading: MacTutor — Isaac Newton

1646–1716 · Germany

Gottfried Wilhelm Leibniz

Leibniz arrived at calculus independently of Newton and published it first (1684). His lasting gift is the notation: the differentials dy/dx, the integral sign ∫, and the word “function.” His symbols were so well designed that we still use them three centuries later.

Why it lands in class: when students use the chain rule or substitution, they are thinking in Leibniz's language. That is not trivia — good notation is what makes the operations feel inevitable rather than magic.

Further reading: MacTutor — Gottfried Leibniz

1789–1857 · France

Augustin-Louis Cauchy

Calculus worked before Cauchy, but it was not yet on solid ground. He built the foundations: the derivative defined as a limit, continuity as a precise property, and the convergence tests that still carry his name. His courses at the École Polytechnique turned analysis into the rigorous subject it became.

Why it lands in class: the limit definitions students meet in their first week are Cauchy's. He is the reason “approaches” can be made exact instead of hand-waved.

Further reading: MacTutor — Augustin-Louis Cauchy

1815–1897 · Germany

Karl Weierstrass

Weierstrass finished the job Cauchy started. He gave analysis the formal limit definition — the arithmetic of “for every epsilon there is a delta” — and in 1872 shocked the field with a function that is continuous everywhere and differentiable nowhere. Both are still standard syllabus material.

Why it lands in class: his counterexample is the cleanest way to break the assumption that “continuous” means “smooth.” Hand a strong student that surprise and you have taught differentiability proper.

Further reading: MacTutor — Karl Weierstrass

1718–1799 · Italy

Maria Gaetana Agnesi

Agnesi wrote Instituzioni analitiche (1748), the first comprehensive calculus textbook and one of the clearest of its era — so clear that it was translated and used across Europe. The curve named after her, the “witch of Agnesi,” still appears in graphing exercises. Bologna offered her a chair in mathematics, an honour almost unheard of for a woman at the time.

Why it lands in class: Agnesi is the reminder that calculus was never only one story. She also gives students a curve with a memorable name and a tidy equation to plot.

Further reading: MacTutor — Maria Gaetana Agnesi

1707–1783 · Switzerland, Russia and Prussia

Leonhard Euler

The most prolific mathematician who ever lived, and the one whose shorthand is now unavoidable. Euler gave us f(x), the sigma sign for a sum, and the letter e; he found the exact sum of 1/n² (the Basel problem); and eiπ + 1 = 0 ties together five of the most famous constants there are. He kept publishing for years after going blind.

Why it lands in class: every time a student writes f(x) or presses ex on a calculator, they are using Euler’s notation. His exponential connects the growth-and-decay problems in the syllabus to the calculus they lead into.

Further reading: MacTutor — Leonhard Euler

1826–1866 · Germany

Bernhard Riemann

Riemann turned the integral from an intuition into a definition. The Riemann sum — slicing an area into rectangles and taking a limit — is his, and it is still how textbooks introduce integration. In a short life he also rebuilt geometry on new foundations, groundwork Einstein later used, and left the Riemann hypothesis, perhaps the most famous open problem in mathematics.

Why it lands in class: the rectangles students draw under a curve are Riemann’s. Showing them why the limit of those sums is the exact area is showing them the definition itself, not a trick.

Further reading: MacTutor — Bernhard Riemann

1850–1891 · Russia and Sweden

Sofia Kovalevskaya

Barred from university in her own country because she was a woman, Kovalevskaya studied abroad, proved the Cauchy–Kovalevskaya theorem on differential equations, and in 1884 became the first woman to hold a chair in mathematics, at Stockholm. The recognition came only after doors had been shut in her face, repeatedly.

Why it lands in class: she is the honest answer to “who does mathematics?” — a person who did first-rank work while being told the work was not hers to do.

Further reading: MacTutor — Sofia Kovalevskaya

1736–1813 · Italy and France

Joseph-Louis Lagrange

Lagrange gave calculus the notation students still write: the prime, f′(x), for a derivative. He also cast the mean value theorem in the form we teach (“the mean-value form”) and built a whole mechanics on the principle of least action, work that underlies modern physics. Napoleon made him a count.

Why it lands in class: the prime is Lagrange’s, and the Mean Value Theorem — the bridge between a derivative and an average rate of change — carries the modern statement of his name.

Further reading: MacTutor — Joseph-Louis Lagrange

1601–1665 · France

Pierre de Fermat

Fermat worked out how to find the greatest and least values of a curve — and the tangents to it — decades before calculus had a name. His “method of adequality” is the ancestor of setting a derivative to zero: at a peak or a trough, the slope vanishes. A lawyer and judge by trade, he did mathematics as a hobby and still left a mark on nearly every branch of it.

Why it lands in class: the rule “a maximum or minimum is where the derivative is zero” starts with Fermat, and the famous “last theorem” is his too.

Further reading: MacTutor — Pierre de Fermat

1685–1731 · England

Brook Taylor

Taylor’s name is on the expansion that turns a smooth function into a sum of powers of x — the series that makes polynomial approximation possible. He also invented integration by parts and opened a branch now called the calculus of finite differences.

Why it lands in class: the Taylor series is how a calculator produces sin x, cos x and ex. Showing students that a curve becomes a polynomial they can add up turns “approximation” from a trick into a reason.

Further reading: MacTutor — Brook Taylor

1698–1746 · Scotland

Colin Maclaurin

Maclaurin wrote the first systematic exposition of Newton’s fluxions, in part to answer Bishop Berkeley’s charge that the new calculus rested on shaky foundations. The Maclaurin series — a Taylor series centred at zero — carries his name, and so does the integral test for the convergence of a series.

Why it lands in class: the series students expand at x = 0 and the convergence test they apply to 1/np are both his. He is also a neat story: rigour arrived, in part, because a critic attacked.

Further reading: MacTutor — Colin Maclaurin

1768–1830 · France

Joseph Fourier

Fourier asked how heat diffuses through a solid and answered with a new kind of series: any periodic signal can be built from sines and cosines. That idea — the Fourier series, and the Fourier transform grown from it — now underpins signal processing, acoustics and image compression.

Why it lands in class: Fourier is the bridge from the trigonometry students already know to the analysis behind sound, music and JPEGs. A square wave built out of sine waves is a demonstration worth ten minutes.

Further reading: MacTutor — Joseph Fourier

1777–1855 · Germany

Carl Friedrich Gauss

Gauss worked in nearly every branch of the subject — number theory, analysis, astronomy, geodesy, magnetism and differential geometry — and is often called the Prince of Mathematicians. He showed that the curvature of a surface is unchanged when it is bent without stretching (the theorema egregium), groundwork that led, through Riemann, on to Einstein. He also gave us the bell curve and the method of least squares.

Why it lands in class: the normal distribution, the error function and least-squares fitting all carry his fingerprints, and his curvature theorem is the reason a flat map of the Earth can never be faithful.

Further reading: MacTutor — Carl Friedrich Gauss

1630–1677 · England

Isaac Barrow

Barrow developed tangent methods that came close to the derivative before calculus had a name, and he was the first to recognise that integration and differentiation are inverse operations. He taught Newton at Cambridge and in 1669 resigned the Lucasian Chair so that Newton could take it.

Why it lands in class: the inverse relationship Barrow spotted is the Fundamental Theorem of Calculus in all but name. He is also the honest reminder that even Newton stood on other shoulders.

Further reading: MacTutor — Isaac Barrow

1661–1704 · France

Guillaume de l’Hôpital

L’Hôpital’s Analyse des infiniment petits (1696) was the first textbook written on the differential calculus: tangents and maxima and minima from infinitely small quantities, then points of inflection, curvature and higher derivatives, and in Chapter 9 the rule that still carries his name for a limit whose numerator and denominator both tend to zero. He acknowledged his debt to Leibniz and the Bernoullis in his introduction, and he needed to: when Johann Bernoulli’s course notes came to light in 1921 the book was seen to follow them closely, under an arrangement between the two men that had left Bernoulli unable to complain at the time. Editions kept appearing until 1781, and it set the pattern for the calculus books that followed.

Why it lands in class: the 0/0 limits that l’Hôpital’s rule rescues turn up in every first course, and the naming story is worth two minutes — the name on a result is a piece of history, not a certificate of authorship.

Further reading: MacTutor — Guillaume de l’Hôpital

1882–1935 · Germany and the United States

Emmy Noether

Noether’s theorem came out of a problem in physics. Invited to Göttingen in 1915 to help Hilbert with the mathematics of relativity, she proved that to every infinitesimal transformation of the Lorentz group there corresponds a conservation theorem — in plain terms, a symmetry of a system comes with a quantity that does not change. Einstein, in a letter to Hilbert, called it penetrating mathematical thinking. She went on to reshape algebra, where her study of chain conditions on ideals of rings is why the subject looks the way it does. Dismissed from Göttingen in 1933 as a Jewish mathematician, she moved to Bryn Mawr in Pennsylvania and died there two years later.

Why it lands in class: the conservation laws students take as facts — energy, momentum — are the visible edge of Noether’s theorem. It is the cleanest route from a symmetry a student can see in a formula to a statement about the physical world.

Further reading: MacTutor — Emmy Noether

Current · MIT, United States

Gilbert Strang

Strang came to MIT as an undergraduate, went to Oxford as a Rhodes Scholar, took his doctorate at UCLA and has taught on the MIT faculty since. His teaching reached far beyond one lecture hall: MIT OpenCourseWare carries his linear algebra course and his seventeen-video Highlights of Calculus series, and many universities teach from his textbooks.

Why it lands in class: Highlights of Calculus covers the arc of a first course in seventeen short videos — worth showing in class, and worth sending to the student who missed a week.

Source: Gilbert Strang’s homepage, MIT · Is this you? Ask for a correction or removal

Current · Lamar University, United States

Paul Dawkins

Dawkins teaches at Lamar University, and since 2003 he has put his course notes on the web as Paul’s Online Notes: a complete, free set covering Algebra, Calculus I, II and III and Differential Equations, with practice problems and full solutions. They are written to be usable by anyone, not only his own students — each course assumes nothing beyond the standard prerequisites.

Why it lands in class: this is the second explanation a student needs at eleven at night — worked examples, practice with answers, a list of common errors and a short guide to studying math, all free in one place.

Source: Paul’s Online Notes, Lamar University · Is this you? Ask for a correction or removal

Current · Macalester College, United States

David Bressoud

Bressoud is DeWitt Wallace Professor Emeritus at Macalester College, a former president of the Mathematical Association of America and a former director of the Conference Board of the Mathematical Sciences. His research asks the practical question — what actually happens in a calculus classroom. He led Characteristics of Successful Programs in College Calculus, a five-year NSF study of mainstream Calculus I, then Progress through Calculus, which examined the Precalculus-to-Calculus II sequence and what universities can change to help students succeed, and he ran the project that produced The Role of Calculus in the Transition from High School to College Mathematics, the report of a 2016 workshop.

Why it lands in class: if you want evidence rather than folklore about why students pass or stall in first-year calculus, this is the body of work to start from — and his monthly column keeps it readable.

Source: David Bressoud’s site, Macalester College · Is this you? Ask for a correction or removal

Current · 3Blue1Brown, United States

Grant Sanderson

Sanderson makes the 3Blue1Brown videos, a channel whose whole aim is to explain mathematics visually. It grew out of side projects he built while studying mathematics and computer science at Stanford; after graduating he spent a year at Khan Academy producing videos, articles and exercises, mostly in multivariable calculus, and since the end of 2016 the channel and its companion site have been his main work. The animation engine behind the videos, Manim, is his too.

Why it lands in class: the visual explanations build an idea from a picture before the algebra arrives, which is what the student who can do the steps but cannot say what a derivative means actually needs.

Source: 3Blue1Brown — About · Is this you? Ask for a correction or removal

Current · Wolfram Research, United States

Eric Weisstein

Weisstein studied physics and astronomy at Cornell and Caltech and took his doctorate at Caltech in 1996. In 1995 he began putting a large collection of mathematical facts — accumulated since his teens — onto the early internet, work that helped define how reference material would later be presented online. He joined Wolfram in 1999 and MathWorld was unveiled at mathworld.wolfram.com that same year. Since then he has worked on Wolfram|Alpha, where he maintains the majority of the mathematical domains together with the graph, polyhedron and unit data collections.

Why it lands in class: MathWorld is the reference you reach for when a student asks what a Fresnel integral or a curl actually is — its calculus and analysis section runs from the mean value theorem to divergence, each entry with the notation and the conditions spelled out.

Source: MathWorld — About Eric Weisstein · Is this you? Ask for a correction or removal

Current · Khan Academy, United States

Sal Khan

Khan is founder and CEO of Khan Academy, a nonprofit whose stated mission is to provide a free, world-class education to anyone, anywhere. Its course library includes a complete Calculus 1 course — eight units running from limits and continuity through the derivatives rules, integrals, differential equations and their applications — built from video lessons, practice sets and teacher tools, alongside the rest of its maths, science and test-prep material.

Why it lands in class: it is free at the point of use, so the student who missed the lesson can rewatch the same idea the same evening, and a teacher can assign it without a purchase order.

Source: Khan Academy — Our leadership · Calculus 1 course · Is this you? Ask for a correction or removal

Current · University of Arizona, United States

Deborah Hughes Hallett

Hughes Hallett is Professor of Mathematics at the University of Arizona and a member of its graduate faculty, and Adjunct Professor of Public Policy at the Harvard Kennedy School. She graduated from Cambridge and has taught in Turkey and in Brunei. Her work is on strategies to improve the teaching of mathematics: with Andrew Gleason at Harvard she organised the Calculus Consortium for Higher Education and started a foundation to promote innovative curriculum and pedagogy. She has served on committees for the National Academy of Sciences, is a fellow of the American Association for the Advancement of Science, and is the author or co-author of seven books.

Why it lands in class: how the subject is taught is itself a research question, and she has spent a career on it and built an international consortium around the answer.

Source: Harvard Kennedy School — Deborah Hughes Hallett · Is this you? Ask for a correction or removal

Current · Mathispower4u, United States

James Sousa

Sousa created Mathispower4u, a library of video tutorials that work through examples on camera. The collection is organised course by course, and Calculus I, II and III each have their own video library — alongside arithmetic, algebra, geometry, trigonometry, statistics, linear algebra and differential equations — so a student can go straight to the topic they are missing and watch the whole problem from the first line to the answer.

Why it lands in class: one video, one worked example, at the student’s own pace. That is the shape of help a stuck student actually uses.

Source: Mathispower4u — tutorials by James Sousa · Is this you? Ask for a correction or removal

Historic entries are drawn from the MacTutor biographies; living entries come from the person’s own or their institution’s published pages, and are limited to their professional work. Is one of these you, or do you know someone who belongs here? Email us — corrections and removals on request.