It would be nice to get quantum gravity without resorting to String Theory. Could we say it ties up some loose ends? :)

See http://www.scienceshelf.com/PhysicsTrouble.htm for a recent comparative review of two books on that subject.

I discuss these loose ends in my new book about 20th-century physics, Physics: Decade by Decade.

Fred Bortz -- Science and technology books for young readers (www.fredbortz.com) and Science book reviews (www.scienceshelf.com)