I've gotten some questions asking whether people who don't have a Kindle can read my book. The answer is most definitely yes! The Kindle App is free and there is a version for basically any device. My own physical Kindle mostly just collects dust, but I am an avid user of the app on the Android phone. You do need either a Kindle or the Kindle App to read the book, but IMHO the app is the next generation of reading anyway, so I encourage you to get it with or without What is Math.
This blog features a series of mini-essays about the history and nature of math, and how it fits into the spectrum of human activity. I'm considering putting them together into a book, so comments are encouraged!