Era o Nourse - é O Universo Entre . De uma revisão da Amazônia :
Scientists inadvertently open a doorway into a parallel universe - one appearing so strange as to drive observers insane. All except one; a young woman who learns to enter the other world at will - as later does her son. This is story of his gradually dawning understanding of what the "Threshold" really is - and it's potential as mankind's route to the stars - but there is a problem... the inhabitants of the other universe.