This is a cool book. There are several things going for it that enhance not only the thematics of the volume, but also its usefulness for anyone not familiar with the Martian Tales by Edgar Rice Burroughs. One of the things that's nice about the creature entries is that the descriptions are lifted from the text, so that the supplemental material provided by this work's author adds to the translation from literary construct to a usable game component. As a writer, I can't think of a higher compliment; as an avid reader, this is a great way to invite people to read the novels by sampling some of the text and exposing a new audience to the works being transcribed for play.
As to the art, I'll be honest. The cover isn't my taste, but like the interior artwork, it's a great nod to old school play. One of the fun things here is the way the sword-and-sorcery pulpy roots of gaming are used to draw out the pulp feel of the Edgar Rice Burroughs' novels. In many respects, it's the perfect homage to gaming's roots and these classic sci-fi tales. The author and artists of this book have done their due diligence, making it worth its price.