World of Ptavvs (1966)
World of Ptavvs is a 1966 science fiction in english book written by Larry Niven.
Larry Greenberg's telepathic tendencies had been trained and developed to a critical level. The trouble was that if these psychic interchanges were strong enough, a man could end up not knowing who he really was. But when Larry's mind is taken over by an alien force, he has to fight to retain his sanity - and divert a disaster that threatens all mankind. And when Larry's mind is taken over by a sinister alien force, he has to fight to retain his sanity - and divert a disaster that threatens all mankind...