Michael Frayn 
Sweet Dreams [EPUB ebook] 

Heaven, reported St John in Revelation, was a cubical city 12, 000 furlongs high made of 'pure gold, like unto clear glass'. That was 1, 900 years ago, and Heaven today has changed out of all recognition. So discovers Howard Baker, who, after a car accident on earth finds a celestial metropolis which offers rich opportunities for leisure and enjoyment — but one that also presents a moral and intellectual challenge for the likes of modest, responsiible, likeable, educated men such as Howard.