I purchased this book about eighteen-months ago based on the recommendation of a friend. I was looking to build an arm chair for the final year of my college project and, looking back now one-year on, I really don't think I could've achieved so much without this book.
When viewing a publication that has originated from 'across the pond', there are always going to be conflicts between the terminology we both uses ('rebate' vs. 'rabbet', for example) and working methods that involve the removal or ignorance of appropriate guarding but, that aside, this is a truly excellent reference for anyone designing a chair, regardless of whether it's your first of your fifteenth.
It's a good read, some (if not all) of the varied designs are going to pique an interest with you and you'll learn all about the important of certain angles, heights and how to find a comfortable seating position for several different situations, along the way.
Highly worthy of a place on any woodworker's bookshelf!