(I've read this one once or twice before.)
Wikipedia's entry about this book includes the comment "... features a mild libertarianism that emphasizes sincerity and honesty" which I was seriously tempted to amend to "features libertarianism that Robert A. Heinlein would be proud of." Someone tries to take what's yours, it's okay to shoot them. Strike that: shooting them is the right thing to do.
But that's not really what the story is about: our protagonist is Jack Holloway, a prospector digging for sunstones on the planet Zarathustra. One day he finds a small humanoid creature in his encampment and befriends it. He calls it "Little Fuzzy" and quickly finds that it's intelligent enough that it may qualify as "sapient." Which is a problem for the company that owns the planet, because a sapient species would invalidate their license for an unpopulated planet. So Holloway finds himself caught in the middle of a physical and legal battle while playing host to multiple super-cute humanoids.
This is a spectacularly cute book that tugs at the heart strings. It's not particularly deep, although it does prod a bit at the question of what sapience is, but mostly it's just an exceptionally charming story.
And it's in the public domain, so you can get it from Project Gutenberg.