First, I want to say that I loved this book. It examines the historical introduction zero into our number system (as we found we wanted to do things other than just count), and then it examines the role that zero and its un-identical twin infinity play in several areas of modern, applied math. The conception of the topics and how they were explained were super interesting, calling out connections I hadn't thought of before.
But I also need to say that I'm a physicist, which is not the same as being a mathematician, but I am familiar with the concepts he introduced. This is gonna be a difficult read for the average lay person. I'd say that it's worth it, though. I also think that the book starts simple and gets harder as it goes, hitting calculus halfway, with a bunch of quantum physics thrown in in the last few pages. Even if the last few pages don't make any sense to you, it's worth reading it for what you can get out of the first 150 pages or so. If you're game. But you pretty much need to go in thinking math is interesting so you'll stick with it. If you're not interested, he's not going to pull you in.
For those interested in math, though, I highly recommend it. Chatty style, good conceptual layout.