Proofreading isn't nearly as boring as this book makes it out to be. Sure, you have to stifle the urge to be juvenile when you catch a missing "l" in the word "public" (professionalism goes far, even if you are just a beginner) but the work itself is rewarding and fun for those with the right temperament. This book lacks enthusiasm, maintaining a dry monotone throughout--not a good attitude for a how-to guide. Those who proofread and edit for a living know that all you have to do is Google your grammar or style question to find knowledgeable and interesting discussion about language, punctuation, and techniques. Learning about the process does not have to bore you to insanity. If you're interested in proofreading, I suggest going elsewhere--take an online class, read the countless blogs about editing and proofreading, or find a book with verve.
So much proofreading is done online/digitally/remotely, that much of this book feels outdated. The information is good to know, especially if you want to work as an in-house proofreader for a company--and if you have the luxury of using hard-copy proofs to look at. However, most proofreaders working through the internet will be mainly responsible for finding and fixing errors, and an important skill to have is Word's "track changes" feature--arguably more important than proofreading marks. The word processing program in use will make font consistency, justification, and other considerations a matter of a click of a button, and the client or others readying the document for publication will be responsible for those changes.