The online Science Fiction Encyclopedia has an extended article about Simak. Here’s the link:
http://www.sf-encyclopedia.com/entry/simak_clifford_d
Of course since
City is his best known work it gets some discussion (but there are spoilers).
I find “Huddling Place” a very dark story. Simak has been categorised as being an optimistic “pastoral” science fiction author but I think he is much more nuanced than that. I feel that this story is an example. The role of the robot is particularly important In feeding into Webster’s fears.