Robert Dvorak's insights into selling art are not bad, but not new, either. Much of what is in this book repeats "tried and true" techniques for artists interested in making contacts, extending visibility and taking advantages of opportunities.
However, effective marketing is not the same thing as selling. Marketing involves a thoughful understanding of your core purpose, a sense of values, and a sense of precisely what the intended consumer of your product might reasonably expect to get from your work.
In this case, very little is said about this necessary activity. Instead, much is assumed about the artist's self-knowledge as it relates to whoever might buy the work, and this assumption is not the most effective.
It's a good book, but there is still a great, gaping need for more in this field - where sales and marketing might still be perceived as "evil."