(Disclosure and/or disclaimer: I don't speak for my employer. If you know who my employer is, you might guess I have all kinds of confidential insider Search Engine Optimization secrets, but I don't. I know this book's author; that might bias me to like the book, but I'm honestly pretty darned sure it's a good book.)
This book is a great introduction to internet marketing, specifically how to rank well on Google and other search engines without slitting your own throat. That last clause in that sentence there might have sounded out of place. But the thing is: many people out there sell "snake oil" in this field. They tell you they have a secret way to make you rank better in search engines. They don't tell you that they're going to set up some spammy sites; they wont' tell you that their techniques might get your site de-listed; they won't tell you that their techniques to make your site appeal to search engines might drive away humans. (Remember them? Your customers? They don't understand why that "best bargain cheap digital camera" link is at the bottom of each of your web pages.)
But if all you can tell people is "Beware of snake oil", they'll reasonably ask you "OK, you've told me not to drink the snake oil, but what should I do?" And if you're like me, you impatiently roll your eyes at this point and think "This is going to take forever to explain; I don't want to talk about this." But now I know what to do with these people. I'm going to throw this book Marketing in the Age of Google at them. It's not about the snake oil. It's about how to present web pages so that they "make sense" to search engines as well as they do to humans. There's no startling insights here, but there's clear explanation, with examples. The book points out some common mistakes, shows how to fix them up.
Along the way, there's good advice about information architecture. There's hints for computer programmers developing content management systems (you poor sods). There's more to say in each of these areas, but the book covers the most important parts. And that's what you want in an introduction of course—you don't want folks over-focusing on some nuance that will boost 10% of their score while ignoring the core stuff and letting 90% of their score collapse.
Even if someone doesn't plan to optimize their own site for search engines, they might want to read this book. If they do, they'll have a better idea of what an honest, competent SEO professional talks about. If you're thinking of hiring an SEO consultant and they talk about this stuff, you're probably in pretty good shape. If they try to sell you some technical mumbo-jumbo about multi-tiered linkfarms, you probably want to steer clear of them.