John Brunner 
Web of Everywhere [EPUB ebook] 

He was 'The Visitor’ . . .in a society revolutionised and troubled by a transportation device that let you walk through a door and be anywhere in the world – instantly. He was 'The Visitor’ . . . at a time when unauthorised travel had caused the violent deaths of countless millions and the survivors were quaking in fear.He was 'The Visitor’ . . .in a world where the invasion of privacy was the ultimate crime and where his obsession with visiting places where he had no right to be led him on a perilous adventure towards his own destruction.