Also entitled: Space Family Stone
Edition: Gollancz, 1969
This is one of Heinlein's earlier novels. Like many of his other books of the period, this one is aimed at the young adult market. It tells the story of the Stone family, who leave their comfortable home in Luna City (on the moon) to see the solar system, travelling to Mars and then to the asteroid belt.
It is a story of exploration and the principal interest is in Heinlein's use of a fairly ordinary family - rather at the upper end of the intelligence curve as Heinlein heroes tend to be - in his portrayal of the different ways people will respond to the challenges of the extreme environments which exist on other planets. (It was written at a time when rather less was known about the solar system, Mars in particular, and the conditions are in fact more extreme than those used in the novel. The mathematics of chaos were completely undiscovered, and they would have changed the way he wrote about the asteroids; no mathematics could prove their orbits to come from an exploded planet.)
Aside from the outdated science, the major criticisms I have of this book are sociological. Each community - Luna, Mars and the asteroids - closely mirrors some aspect of small-town American life. This is not intended by Heinlein to make some sort of critical point; science fiction novels criticising contemporary society were not his forté. It has more to do with a lack of imagination; he has simply projected the technological advances in which he is really interested - it's really a "Hey, wow! Spaceflight" novel from the days before Sputnik - against the social background easiest for him to portray and for his audience to understand. Mars is the only place he really has criticisms of, and that is to do with the obsession with commercial gain and taxation he considered more typical of the slightly larger community. It was not until Stranger in a Strange Land that Heinlein broke out of this, and wrote a book truly worth reading by an adult audience.