Nutshell: bucolic twerp with plot-significant eidetic memory defrauds his way aboard spaceship, flirts with rich girl, has a big adventure, &c.
YA and pulpy, but moves quickly, with characteristic heinleinian asides regarding law, politics, and science. Some nifty geeking out on the science of FTL travel.
Some have said that the text lays out a critique of labor unions, which may be the case. But it's not unambiguous, as the setting involves less unions than guilds, a significant distinction. The main guild under examination is the astrogation guild, which purportedly restricts access to the knowledge of astronautical navigation. As one character describes it, though, "there are no 'secrets' to astrogation," which "isn't secret; it is merely difficult" (97). The implication is accordingly not that labor power has joined for the purpose of collective bargaining, but rather that possessers of knowledge have restricted general access to important information. The critique, then, runs less toward the Wagner Act and more to the Copyright and Patent Acts.
Recommended for phlegmatic crustaceans, real four-dimensional chess players, and large louts who arouse the eternal maternal.