This is a collection of 8 stories from the late 50's and early 60's. They have common characters and a pretty consistent setting (though there are some slight inconsistencies from story to story), and share some background material from story to story to the point of annoying repetition, but there is no long-term story arc, development from story to story, or even reference in one story to events in another. The stories are individually quite readable; the characters are thin but the plots are engaging enough. The science is a little weak, but mostly plausible enough, and the stories get into some social and philosophical speculation that is somewhat interesting.
Not great, but I did enjoy the actual reading more than it seems like I should have when I think about the various parts (plot, characterization, suspension of disbelief, etc.), which I guess is the measure of good writing. 8 out of 10.