I'd recommend this book to anyone who's been knitting for a while and wants to learn new techniques - NOT "just" sock knitters. It's certainly not a "how to knit" book, but it covers subjects that could improve any knitter's technique.
The subject of the book is the Art of sock knitting, as practised in Eastern Europe and the Middle East. The Art section of the book is well researched and well presented. The pictures make it fun to read.
The focus of the book is on the Craft by which these works of art are created. This book includes a compendium of cast on techniques, analysis of knitting styles, detailed instruction on how to spin yarn which will wear well and maintain its shape, and great information on designing, especially with multiple colors.
The section on knitting intarsia (multiple colored pictures) IN THE ROUND is worth the cost of the book by itself. There are multiple options for shaping toes and heels, and for solving typical sock knitting and fitting problems as well.