This book is about cleaning up HTML, the markup language used to write web pages. It's a good book. I'm going to kvetch a lot about parts, but... kvetching comes easy. Anyhow.
You know how liberals are famous for losing credibility with normal folks by... by looking at things from both sides out loud, shooting themselves in the foot along the way? This book is kinda like that at first, but it gets better. It loses credibility early on by arguing at length for XHTML over HTML. There is the usual list of reasons that people use when boosting XHTML, none of which apply to folks writing HTML by hand. Yet, that, apparently, is the audience: "Writing correct XHTML is only even mildly challenging when hand authoring in a text editor." That last sentence indicates an author out of touch with reality as most people experience it. This is forgivable, understandable. The author, Elliotte Rusty Harold, has been looking at raw XML more than most people. He has written more books about XML than... he's written a lot. He has no doubt learned to look <through /> a <forest /> of XML-ish <angle /> <brackets /> (in the same way that an experienced LISP programmer (easily) keeps track of a prairie (of parentheses)). But there are other pieces of advice--assign an id to each element, e.g.-- which suggest that he doesn't normally work in raw XHTML (or HTML); no-one could wade through that much clutter. (In his defense, he does back off and suggest that it's enough to add ids for just some of the major elements--but he says the trade-off is for bandwidth; never mind the sanity of the folks trying to read & edit the code later.) And he misspelled Marc MERLIN's last name. And-- a-- and--
And hang on don't run away; there's a lot of good stuff in this book. This book is basically a big list of ways that you can improve your HTML--and other aspects of your web site. I wish more webmasters would read this book. Though not all pieces of advice apply to all sites, many of them... I wish more webmasters were exposed to more of these issues. I suspect that most webmasters aren't aware of many of them. I wish more webmasters studied up on web accessibility. And I don't really think that the author Harold is an insane XML freak who has lost his instinct for XML's unreadability--I looked at his web page and it's in HTML, not XHTML; Harold doesn't force himself to deal with hand-editing XHTML. To be clear: Harold's web page's HTML is quite readable.
I could imagine using this book as a checklist for sprucing up a site--not following all of the pieces of advice, but considering them. It covers a wide swath of ground: encodings, programming, HTTP, SEO, usability... there's plenty of good stuff here. Check it out; keep your grain of salt handy.