In the late 1960s a small group of theorists concluded that quantum field theory could not provide a suitable description for the main problem of the time, that is, to account for hadronic physics. As a result, they began a quest to find an S-matrix that had certain preordained properties. The search culminated in the discovery of such an S-matrix for four, and then any number of, spin-0 particles. By using physical principles and mathematical consistency it was found that these S-matrix elements were part of a larger theory that possessed an infinite number of particles. Remarkably, the early pioneers found the scattering amplitudes for any number, and any type, of these particles; they even found these results at any loop order. It was subsequently realised that this was the theory of string scattering and that the theory was more suited to describe fundamental, rather than hadronic, physics.

Supersymmetry was unearthed from the world-sheet action for the ten-dimensional string and also found by independent quantum field theory considerations in Russia. Supersymmetry is entwined with string theory, but it is an independent subject. Hopefully, it will be found at the Large Hadron Collider at CERN, but even if it is, this is unlikely to be direct evidence for string theory.