Martian Time-Slip, Philip K. Dick
I suppose this a classic version of Mars of a desert mars with the little remaining water in the canals. Settlers have arrived from Earth and are doing badly. The story features autism and schizophrenia and the alternate world views that they create. The title refers to an attempt take advantage of these illness to look into the future. Didn't enjoy this one, several of the characters got on my nerves.
