Theodore Sturgeon, Robert Silverberg

No two Science Fiction authors changed the genre so much, in that period of time known as New Wave, late fifties through the mid seventies.

Both men did what none had successfully done before, and few have done since, is focus soley on the human psyce in a speculative future, or in a speculative situation, leaving the tehcnology aspects of the speculation to be background objects. Important background objects, certainly, since telepathy, spaceflight, alternate energies, unique planets, often servered to define the characters basic motivations, but thats the extent. You had to know the "science" in the story to understand the motivations, but neither author wanted you to pay much more attention than that.
By the way, this became more pronounced in Sturgeon as he aged, and less pronounced in Silverberg.
What did this give us? It gave us two startling authors who pressed the boundries of what people would feel and think beyond the reality we live in today.
Silverberg taught us what it feels like to be a telepath in "Dying Inside", for example, not waht you could do with telepathy. Sturgeon described the morality and ethics of a group mind in "And baby makes Three", didn't focus on the superbrain.

And beyond the basic human focus, both went to extremes in emotional depth that science fiction had not had before. Sturgeon to the transendental, the upbeat philospher of SF. Silverberg to the depths, the dark vision of the emotional wreakage that any technology or speculative future could create.

Read them