  While perturbative techniques work extremely well for weakly interacting
field theories (e.g. QED), they are not useful when studying strongly
interacting field theories (e.g. QCD at low energies). In this paper we review
Heisenberg's idea about quantizing strongly interacting, non-linear fields, and
an approximate method of solving the infinite set of Tamm-Dankoff equations is
suggested. We then apply this procedure to an infinite energy, classical flux
tube-like solution of SU(2) Yang-Mills theory and show that this quantization
procedure ameliorates some of the bad behaviour of the classical solution. We
also discuss the possible application of this quantization procedure to a
recently proposed strongly interacting phonon model of High-$T_c$
superconductors.
