Citizen of the Galaxy is classic Heinlein. In this case he takes the reader to a world where slavery is legal, and a young boy with no past is being sold to a beggar. However, that beggar turns out to be a spy working to end slavery.

From him, the young slave Thorby learns how to beg but also many tricks of his adoptive father’s trade. When his adoptive father is killed, he knows to go to a Trader ship to pass one last message.

Citizen of the Galaxy is aimed at juveniles, but it’s still not a bad read for adults. People new to science fiction won’t find this one intimidating, and it’s a great look at how well Heinlein could craft various cultures.