Wow!! What a book - Kate Atherly is a force. I mean, if it's not in this book, you don't need to the information. Trust me on that.
From the proper fit of a sock to a thesis on yarn, needles & gauge to stitch patterns and adjustments for "non-average" feel (how kind of her to say "non-average"), this book has it ALL.
I have been knitting socks for awhile and have knit LOTS of socks, mostly successfully. While some of the "sock maths" kind of made my eyes glaze over (turns out I need my info in just tiny little bites), this book is amazing. In fact, a little takeaway for me is that I am changing the toe I will be using on socks. (Let's hear it for the "half & half" toe & why am I just now hearing about this toe??)