If there’s one thing I’ve learned in my years of reading about and contributing to science, it’s the old cliche that the more I learn, the more I realize how much I don’t know. The method of science has revealed a whole lot about the universe we live in, but even the most well-established facts can be utterly mysterious if examined in depth. Most of this mystery is still too unfathomable to even be labeled as a mystery, beyond even the wildest speculation. However, there are some things we know enough about to ask good questions, but not yet enough to provide good answers. Michael Hanlon explores ten of these questions in this book.

The title is a bit misleading; this is not a comprehensive “guide”, but a rather random selection of ten mysteries. Some are what you’d expect – e.g., what is dark matter? What are consciousness and identity? But there are also some quirky topics you wouldn’t expect here – e.g., what really causes obesity? What should we do with stupid people? I found these rarely-tackled topics to be the most interesting.

It’s a quick read, written in an informal style and never delving too deep into any one topic. It’s just enough to stimulate your appetite for more information, but unfortunately Hanlon rarely provides sources for the science mentioned. That’s somewhat forgivable – this is, after all, a book of questions, not answers. Less forgivable is the preponderance of typos and shoddy writing (e.g., why does everyone have so much trouble distinguishing “which” and “that”?). I thought I was just being picky, but I got the book from the library and whoever read it before me went to the trouble of circling and correcting each of the many mistakes. Hilarious.

This book should be a light, entertaining read for both scientists and non-scientists. I think it would also be a great wake-up call for people who identify with the so-called “skeptical movement.” Skepticism is obviously a requirement for good science, but I think it is often taken too far, to the point where skeptics can claim that we already know everything there is to know about the universe (and therefore anything that contradicts current knowledge must be wrong). This book is just one reminder that no, actually, we know very little about the universe. Mystery is what makes science so exciting.