Panicky Malthusianism meets bad physics in the least of the classic Heinlein juveniles
Farmer in the Sky
By Robert A. Heinlein
I think Heinlein worked on his technique all through the juveniles but to my eye 1950’s Farmer in the Sky, while introducing themes that would persist through the rest of his career, is a half step back, filled with pacing issues and the decision to highlight aspects of his world-building that he probably should have tried very hard to distract people from.
[spoiler warnings]