Big Planet is home some of the rejects and ne’er do wells floating around the galaxy. Very earthlike, but much larger, hence the name Big Planet. Good guy Claude Glystra and his team are going to finally clean up and stop the slave trade and arms importing on the planet. Of course, they run into trouble and have to make their way back to the Earth Enclave, the safest point. This means having to deal with some petty tyrants and other folks who want them gone. Like a Star Trek landing party, they run into some interesting societies and customs along the way.
Vance had an expansive career and died last May at age 96. He had quite the career. You can read the Wikipedia article here.