Over the last few years the words string theory have nudged their way into public consciousness. It's a theory of everything in which everything's made of strings — or something like that. But why strings? What do they do? Where did the idea come from and why do we need such a theory? David Berman has an equation-free introduction for beginners.

A new mathematical model explores the time before the big bang

String theory finally looks like it is tying the knot with established physics.

Mathematicians pin down symmetry

Scientists develop ways of testing string theory against reality

Nurturing the future of observational cosmology

Theoretical physicists are searching for a 'Theory of Everything' to reconcile quantum mechanics and relativity - the two great physical theories of the twentieth century. String theory is a current hot favourite, and some of the world's most eminent physicists tell us why.

Plus is very proud to present Professor Stephen Hawking's own Birthday Symposium address.