Hal Clement (Harry C. Stubbs)A quiet and underrated master of "hard science" fiction who, among other things, foresaw integrated circuits back in the 1940s.
Isaac AsimovOne of the most prolific writers in history, on any imaginable subject. Cared little for art but created lasting and memorable tales.
...depending on how I answer the 'glass is half-full or half-empty' question. I think I can live with either of them.
Onwards and upwards!