As a long-time freelance writer running a freelancing advice site, I read a lot of books that offer tips and resources to freelancers. This was the worst one I've read.
The crux of the book is that if you want to make a good living as a writer, you shouldn't be a writer, but the manager of a writing business. Since the author is a "serial entrepreneur" and not a writer,perhaps he doesn't understand that most people pursuing a freelance writing career want to...write.
He "proves" that it's not possible to make a good living as a solo writer mathematically, by assuming a goal of $100,000 annually and then demonstrating that there aren't enough hours in the day to earn that amount writing articles at $25 each. That's true, but it's hard to imagine why anyone would attempt to build a full-time career writing at those rates. There are, of course, many writers who make $100k/year from their own writing. They do it by cultivating their craft and expertise and charging quite a lot more than $25/article.
Then, after explaining in detail why he believes that you can't make a decent living on $25 articles, Kerns goes on to tell you the way to make good money is to hire a bunch of other writers and pay them $10/article. (Well, in one calculation--in others, he's suggesting paying writers $2.50/article) Similarly, after talking about how miserable your life will be if you have to crank out content 12 hours/day, he suggests that you require your writers to produce ten articles per day--in other words, work 50 hours/week or more for a $20,000 (or less) annual salary with no benefits.
Ultimately, after a long period of hiring and training a writer, increasing your business, rinsing and repeating, you will eventually get to the point where you have enough income that you can take the time to write what you want to write--something you could have achieved in much less time and without all of the complicated business aspects of an "empire" simply by developing an area of expertise and charging decent rates for your write.
But, there's more. This book is filled with misinformation and misdefined terms. "Long tail" keywords are absurdely defined as keyword phrases of more than one word (they're actually more specific terms that bring in a lower volume of highly targeted traffic, making up the "long tail" of your traffic graph), you're advised that it's "perfectly okay" to include a link to your website in your signature block on groups and forums (though many, especially professional groups, explicitly prohibit this), told bid sites will "protect you" from unfair feedback (though most bid sites don't meddle in feedback matters at all, save very specific TOS violations)...and so on, and so on, and so on.
There are a few useful tidbits here and there, but if you're not already an experienced writer/freelancer/entrepreneur, it will be very difficult to tell them apart from the blatant inaccuracies.