Wow, I just finished reading "Mortal Engines", a collection of short stories by Stanislaw Lem, and have moved onto "The Three Stigmata of Palmer Eldritch" by PK Dick. The kind of coincidence that would no doubt inspire Dick to write something!
The last story in Mortal Engines - "The Mask" - ranked easily as good as Dick's work and perhaps even bested it in its narrative of eccentric psychological states.