This is what geeks me out. I picked up this book at a thrift store. Originally written in 1944 this is the first English printing 1958. Rene Barjavel was the first person to suggest “The Grandfather Paradox”. If one were to travel back in time and kill your own grandfather, you could not exist. This is the VERY FIRST book that ever used this rule of time travel. Pristine condition for being 66 years old. Yes, it will stay on my personal shelf until sold.