The concept of this old sci-fi anthology series was that 8 authors would contribute 4 short stories/novellas, one to be published in each volume, all set in their own universes, yet could generally stand alone if you only found vol 2, for example.
I originally picked it up for the Anne McCaffrey story--the prototype for her Crystal Singer series (and the story in the 4th volume absolutedly stunned me at 1st reading--it was so unlike her...but further deponent sayeth not, as they say). But in re-reading it, I found a lot of old classic sci-fi authors and added some of their books to my To-Read list. There were post-apocalyptic Earths, colonists and traders with foreign worlds, robots ruling the Earth, and so on. These are stories in old sci-fi traditions: even when depressing, they have breadth, scope, depth... Well worth the read--the entire series.