  The nonperturbative Hamiltonian eigenvalue problem for bound states of a
quantum field theory is formulated in terms of Dirac's light-front coordinates
and then approximated by the exponential-operator technique of the many-body
coupled-cluster method. This approximation eliminates any need for the usual
approximation of Fock-space truncation. Instead, the exponentiated operator is
truncated, and the terms retained are determined by a set of nonlinear integral
equations. These equations are solved simultaneously with an effective
eigenvalue problem in the valence sector, where the number of constituents is
small. Matrix elements can be calculated, with extensions of techniques from
many-body coupled-cluster theory, to obtain form factors and other observables.
