This is a 1973 collection of nine Sci Fi stories and novelettes by Vance, totaling about 300 pages. "The Moon Moth", in particular, is one of Vance's best and is perhaps the star of the collection. There are also 3 Magnus Ridolph tales. Contents include:
"The World Between" (1953): Blue-Star explorers have claimed a potentially habitable planet, and seek to terraform it, while a rival space empire, the Kays, engages in ecological sabotage. It has an interesting final twist that, not being fully spelled out, I did not get on first reading. Alternate title: "Ecological Onslaught". (28 pages).
"The Moon Moth" (1961): The misadventures of Edwer Thissel, Earth consul, and his bumbling efforts to adjust to the strange society of the planet Sirene, where the inhabitants all wear distinctive masks, and communicate by playing musical instruments. Unique, atmospheric and highly memorable. (36 pages).
"The Brain of the Galaxy" (1951): A contest to determine the succession of a galactic ruler. I liked some of the little contest episodes, but I was not wild about the central premise, and found the whole to be less than the sum of its parts. Author's title: "The New Prime". (24 pages).
"The Devil on Salvation Bluff" (1955): Missionaries on an alien planet are dismayed by its chaotic patterns and equally chaotic natives. (22 pages).
"The Men Return" (1957). Silly but enjoyable little tale about relics of humanity trapped in a "pocket of non-causality". (9 pages).
"The Kokod Warriors" (1952), "The King of Thieves" (1949) and "Coup de Grace" (1957) are three somewhat comical adventures starring Magnus Ridolph, a sort of interplanetary troubleshooter. All three, particularly THE KOKOD WARRIORS are fun, and are arguably among the best of the ten Ridolph tales, though personally I would have picked "The Howling Bounders" or "The Spa of the Stars" over "King of Thieves." All can be found in THE MANY WORLDS OF MAGNUS RIDOLPH, which in my opinion is worth getting, making this part of the volume potentially redundant. (36, 19 and 18 pages respectively).
"The Brains of Earth" (1966): About an alien race waging war against "nopols" a invisible, intangible parasitic/symbiotic creature which attaches itself to humanoid brains. Having purged the nopols on their home planet, they now seek to carry the war to the nopol's home planet, Nopalgarth, also known as Earth. An interesting novella that plays with quasi-spiritual concepts, but where the setup is more impressive than the disappointing resolution. Author's title: "Nopalgarth". (101 pages).