Most applications of mathematics are hidden behind the scenes. No one wants to have to learn spherical trigonometry to use their car’s satellite navigation, so the mathematics is squirreled away inside electronics and software. As a result, no one realizes the mathematics is there. In fact, satellite navigation relies on at least eight different areas of mathematics, including Einstein’s relativity and, amazingly, number theory. Some of the topics in the book have important practical uses: minimal surfaces, which arose from questions about soap bubbles, have applications to biology (the iridescent colors on beetles’ wings), to nanotechnology (manufacturing very small substances and devices), and to cosmology (the nature of the universe and our place within it). Finding the shortest route between two towns is a key part of satellite navigation for cars and other vehicles, and the same mathematics can be used to plan efficient delivery routes. Sphere packing has connections to error-correcting codes in digital communications. Geodesics govern the paths aircraft fly along and the fundamental physics of gravity.  The mathematics behind AI has led to huge progress on how proteins fold, the subject of one chapter, which is important in medicine.

How did I get into these activities? With hindsight it was inevitable. I’ve always had a journalistic streak —I enjoy writing for its own sake. I loved mathematics, and I wanted everyone else to feel some part of that love, instead of vowing never to touch the subject again as soon as they left school. My father had found a 1920s typewriter in the basement of the bank where he worked, been allowed to take it away, and gave it to me. Well, if you’ve got  typewriter, you have to use it.

As a PhD student at Warwick, I was one of a group of students who produced a mathematical ‘fanzine’, Manifold. I started writing for magazines like New Scientist. A puzzle book for children paid the deposit on our first house. The first real breakthrough was a book on ‘chaos theory’ — Does God Play Dice?  I wrote the Mathematical Recreations column in Scientific American for 12 years. Did some radio and TV. I acquired a literary agent and became a semi-professional writer. I gave the Christmas Lectures for BBC TV in 1997, and Warwick relieved me of undergraduate teaching duties to focus on outreach. I continued doing research — and still do, sixteen years after ‘retiring’. (My wife laughs when I say that.)

A second breakthrough was when Profile books published Professor Stewart’s Cabinet of Mathematical Curiosities in 2008, which went to number 6 on Amazon UK. Since then Profile has published most of my popular mathematics books. Some are about areas closely related to my own research, so that feeds into them. But my journalistic instincts lead me to write about any topic that I find interesting. To me, my research and my writing are just different parts of one big picture.

Ongoing thread. More from Ian Stewart to follow.