Salmon have an heriditary instinct to swim upriver against the stream. The same inate drive pushes some scientists to replace theories of the day with their own perceptions. These avant garde specialists are unafraid to tackle mainstream ideas in the belief that their views are correct. Jane Gregory's book, Fred Hoyle's Universe shows how Fred Hoyle fits this description of an original thinker in his near ceaseless, lifetime espousement of fresh ideas. The current of conformity never seemed to be too daunting as he went about following his own pursuits.