  We discuss the physics and computation of lattice QCD, a space-time lattice
formulation of quantum chromodynamics, and Kenneth Wilson's seminal role in its
development. We start with the fundamental issue of confinement of quarks in
the theory of the strong interactions, and discuss how lattice QCD provides a
framework for understanding this phenomenon. A conceptual issue with lattice
QCD is a conflict of space-time lattice with chiral symmetry of quarks. We
discuss how this problem is resolved. Since lattice QCD is a non-linear quantum
dynamical system with infinite degrees of freedom, quantities which are
analytically calculable are limited. On the other hand, it provides an ideal
case of massively parallel numerical computations. We review the long and
distinguished history of parallel-architecture supercomputers designed and
built for lattice QCD. We discuss algorithmic developments, in particular the
difficulties posed by the fermionic nature of quarks, and their resolution. The
triad of efforts toward better understanding of physics, better algorithms, and
more powerful supercomputers have produced major breakthroughs in our
understanding of the strong interactions. We review the salient results of this
effort in understanding the hadron spectrum, the Cabibbo-Kobayashi-Maskawa
matrix elements and CP violation, and quark-gluon plasma at high temperatures.
We conclude with a brief summary and a future perspective.
