"From the Classic "Viagens" Books by L. Sprague de Camp
Swashbuckling Adventure in Space"
From the back cover:
"Play out thrilling adventures from scinece fiction's Golden Age in the Viagens Interplanetarias setting of L. Sprague de Camp's stories set on the planet Krishna!
"The natives are all too human – except for the green skin, the feathery antennae, the eggs ... "Protected" from technology by interstellar law, armored knights clash in a wilderness of blue woods while square-rigged war galleys patrol the inland seas. It will take a quick sword and quicker wits if a visitor is to survive [...]"
"Discover space adventure the way it ought to be."
The introduction is written by L. Sprague de Camp himself.