We live in exciting times. The frontiers of physics have been pushed to unprecedented horizons. The Holy Grail of fundamental physics research today is to find and describe a theory that explains, at least in principle, all physical phenomena, which in turns explains chemistry, biology and other material sciences. This, however, is not without controversy. Currently, the most popular candidate for such a theory is known as string or superstring theory. It suffers from the problem of being a purely mathematical science with no experimental backing, and belief in it has been criticized as bordering on “faith” as opposed to scientific scrutiny. On the other hand the recent switching-on of our most advanced experimental tool, the Large Hadron Collider in Switzerland, gives new hope in our search for clues as to what the universe is made of on a fundamental level. What happened exactly on, or even before, the Big Bang? Where are we coming from and where are we going? Questions that have never been addressed before by physicists. The game is afoot and the search is on. This book contains articles by leading physicists describing the current situation. Among them are proponents as well as opponents of string theory, and proponents of other ideas such as Loop quantum gravity, commutative geometry, and others.