Surely the reader had come across situations where he would have given his life to get the “final answer”, the reason for our existence, a Theory of Everything, a true World Formula that contains it all… So did the author of this book. There was this deep-seated and forever unquenchable thirst for fundamental explanations on the one hand, and then there was this very special motivation from somebody else who needed this knowledge, on the other: “How to explain the world to my dying child?” Perhaps this provided the driving force to actually start this million-mile-long journey with the first small—and very tentative—step. Considering all the efforts taken, money spent, disputes fought, papers and books written, and conferences held, it is almost shocking to find that, in principle, the World Formula was already there. It was David Hilbert who wrote it down during World War I in November 1915. The complexity of the math involved was not the only thing that obscured what should have been obvious. This book explains why apparently only very few people had realized his immortal stroke of genius.