'Reality is merely an illusion, albeit a very persistent one,' said Albert Einstein. Is the toilet seat cleaner than the office desk? Did Man really land on the Moon? Is the Black Box black? Does a soul weigh 21 grams at the time of human death? Did Einstein fail school? Why isn't a quantum leap huge? Do we really use only 10% of our brain? Did hydrogen seal the fate of the Hindenburg airship? Does a duckᱠquack echo? Is there really a truth serum? Is a camel's hump full of water? And is it really written in the stars? Dr Karl Kruszelnicki is the Julius Sumner Miller Fellow at the University of Sydney. He appears on triple J and other ABC radio stations, the BBC and is a regular on Channel 7's 'Sunrise' program. this is Dr Karl's 23rd (ooh that's a prime number) book, based on his popular column 'Mythconceptions'.