  The coupled cluster method (CCM) is one of the most successful and
universally applicable techniques in quantum many-body theory. The intrinsic
nonlinear and non-perturbative nature of the method is considered to be one of
its advantages. We present here a combination of CCM with the Wilsonian
renormalization group which leads to a powerful framework for construction of
effective Hamiltonian field theories. As a toy example we obtain the two-loop
renormalized $\phi^{4}$ theory.
