The book's authors are Nathanael Kuipers, a former LEGO Product Developer, and Graphic Designer Mattia Zamboni, and the two have put together a beautiful book giving step-by-step instructions to build a new collection of models with the Red Car set. The book starts off with fairly simple creations like a hot rod, but it eventually has the reader putting together 18-wheeler cabs and construction equipment with multiple functional pieces.
While the hot rod is the book's first, and easiest, set of instructions, it shows several interesting design ideas and actually kicks the book off with what appears to be a fairly common build-choice in these models. That is to say, it makes extensive use of the block measurements that can allow pieces to face in directions other than straight up.
For the hot rod, this is just the bumper of the car, but as the book progresses, detail pieces like spoilers, roll cages, the curved lines of an F1 racing car and even the entire underside of the excavator model will have tiles and blocks facing atypical directions. It is obvious, even if you aren't building the models alongside of the book, that knowing how to re-orient the blocks will open up design options that will help sell the look of the model you are building.
The LEGO Build-It Book, Volume 2: More Amazing Vehicles slowly ramps up the difficulty with a gran turismo racing car to a chopper motorcycle with steering capabilities and even a roadster. The models get more complicated with a tow truck and a dune buggy that has an interesting tilted rear axle and a forklift that has limited lifting capabilities.
The book wraps up with some fairly complicated models. The big rig comes complete with the ability to fold forward the cab and take a look at the engine, while the sleek lines of the F1 racer ends up being more complicated than it appears at first glance. The book's last model is the aforementioned excavator that not only has an articulate digging arm, but a tiltable front blade and 360 degrees of motion around its center.
While there aren't a lot of words in the book, there are a couple of sections that convey both basic and advanced building concepts, but really, those concepts are better seen by someone who pays serious attention to how the pieces fit together and where they all end up. Anyone looking to strengthen their building skills should be interested in The LEGO Build-It Book, Volume 2: More Amazing Vehicles.
