# The Calculus Diaries by Jennifer Ouellette

I finished Jennifer Ouellette’s new book a few weeks ago, shortly after my trip to Alabama, but it’s taken me a long time to get around to reviewing it due to a combination of too much work and being a Bad Person. There’s finally a tiny break in the storm of work, though, so here’s a slightly belated review.

The Calculus Diaries is not a book that will teach you how to do math. There aren’t worked examples, detailed derivations, or homework problems in the main text. It might, however, teach you not to fear math, as it provides a witty and accessible explanation of the key concepts behind calculus, and how those ideas show up in everyday life.

For all its fearsome reputation, calculus is really very simple in concept: it’s a mathematical toolbox for dealing with change. Differential calculus (derivatives) is the study of individual small changes– how mathematical functions change when you change their inputs– and integral calculus is the study of the cumulative effect of lots of little changes. Those core concepts can get lost in a haze of calculation when you first encounter the subject in school, but in the end, everything flows from those two ideas.

In this book, Ouellette spells those concepts out very clearly, and explains how they apply to a wide range of real-life situations: amusement park rides, games of chance, population biology. OK, that’s “real-life” for values of real life that include zombie apocalypses, but the point is, there are lots of engaging examples drawn from everyday experience and pop culture. Each example in the book includes a clear explanation of how it can be understood in terms of individual changes or cumulative effects, setting out the essential relationships in words, not equations, and explaining the important properties of the solution. As a bonus, it also includes some of the many colorful historical anecdotes about the development of key ideas in mathematics.

I’m not really the target market for this, in a lot of ways– I’d probably be happier with the equations written out in mathematical notation– but I know enough about the target market to recognize it as something that is pitched to the right level for the audience that needs this book. The idea of integrals as the sum of a lot of little steps is something that we spend a lot of time banging on in the introductory physics curriculum, and for many of these students, it would probably be more effective to explain it first without equations, and come back to the math later (insert obligatory grumble about our too-short academic terms).

(There is an appendix with all the mathematical equations and functions spelled out. I’m obscurely proud to say that I was the second great big dork to point out that there’s a typo in one of the equations…)

This is a fast-moving and engagingly written book about what math means. It won’t teach you how to calculate anything, but if you’re not already mathematically inclined, it’s a good way to get a sense of the attraction of math for those who are.

1. #1 featherefrog
October 28, 2010

2. #2 featheredfrog
October 28, 2010

ISBN-13: 9780143117377

3. #3 Steven Doyle
December 24, 2010

I’m just partway through the book, but agree with your review so far. I may not be able to finish it, because it’s giving me a headache — I think because I’m not the innumerate target audience, and she assumes I understand less than I do. (And assumes this in an irritating way, by beginning sentences with “I know what you’re thinking …” One should never do this non-ironically in a nonfiction book.)

The approach of explaining the concepts before getting to equations is a good one, but when she does get into the actual math operations, there are problems. E.g., the chart on p. 51 seems to have a wrong variable (g instead of e).

Then she keeps saying “the derivative is a process of subtraction and division”, and “the integral is a process of multiplication and addition”. Why is she transposing multiplication and division?

4. #4 Steven Doyle
June 25, 2011

Belatedly adding: I think the problem is the author is not truly comfortable with equations, and doesn’t realize when there’s a disconnect between what she’s just stated in words, and the formula she just used. On the face of it, having a non-mathematician write a book for other non-mathematicians sounds like a good idea, but I think what was really needed was a mathematician who knows how to talk to laymen.

5. #5 Jackson
November 3, 2011

Do you think you could recommend a similar but more math heavy book? I have to wait until the next fall semester to take Calc III and I was hoping to find an engaging way to keep my skill set up