It's also terribly typeset on Kindle. I only mention because I also recommended this book a month or so ago on the post about the quintic . I gave this a 3/5 on Amazon UK. Here's my review :
> This review relates to the (shockingly expensive) kindle edition. At almost £20 you would expect the publishers to have proofed this a lot more. There are references throughout to pages and theorems that have no link (and are therefore difficult to follow on an e-reader), some footnotes are instead displayed inline which is confusing, in other places there are errors in the rendered formulas that force you to stop and re-read it to work out what bit was printed wrong.
> The material itself is certainly interesting but the authors are I think deluding themselves if they believe this a book accessible to someone with just a knowledge of calculus. I've studied group theory formally and this book is heavy going. Part 1 is reasonable but beyond that, it quickly becomes dense and terse and far too short. I had high hopes for this book but it, unfortunately, falls short of the mark. I wish it was twice the length and with more care to the proofing during the ebook creation.
On the topic of the Monster group, there was a very much pop-math book about it that I read called "Symmetry and the Monster". It's at the total opposite end of the spectrum compared to Fearless Symmetry (which deals with Galois theory). It's a good casual read  but don't expect deep insight. I would really love if there was an author like Paul Nahin  writing books on abstract mathematics in a similar style. If you are into just generally "advanced" books that are very readable he is an absolute joy.
 https://www.amazon.co.uk/Symmetry-Monster-Greatest-Quests-Ma... https://www.amazon.com/Paul-J.-Nahin/e/B001HCS1XI