  We propose an identification of the conformal field theory underlying
Lipatov's spin-chain model of high-energy scattering in perturbative QCD. It is
a twisted N=2 supersymmetric topological field theory, which arises as the
limiting case of the SL(2,R)/U(1) non-linear sigma model that also plays a role
in describing the Quantum Hall effect and black holes in string theory. The
doubly-infinite set of non-trivial integrals of motion of the high-energy
spin-chain model displayed by Faddeev and Korchemsky are identified as the
Cartan subalgebra of a W_{\infty} \otimes W_{\infty} bosonic sub-symmetry
possessed by this topological theory. The renormalization group and an analysis
of instanton perturbations yield some understanding why this particular
topological spin-chain model emerges in the high-energy limit, and provide a
new estimate of the asymptotic behaviour of multi-Reggeized-gluon exchange.
