If you are embarking on a career in proofreading in the UK, don’t buy this book. From a professional proofreadinq point of view, the structure of the book is both clumsy and patronising, the text seemingly being aimed at American middle managers who, having lost their secretaries, now have to do their own admin work. Additionally, as the book is American, the proofreadinq marks are not based on the British Standards so will be of no use in the UK. One particularly useless piece of advice is to kick a tree to free your mind from distraction (or 'internal noise' as the author calls it).
Unless US style self-help titles are your thing, this book probably isn't for you. Oh, and I found uncorrected errors in it!