We construct the minimal effective chiral pion-nucleon SU(2) Lagrangian at
fourth order in the chiral expansion. The Lagrangian contains 118 in principle
measurable terms. We develop both the relativistic as well as the heavy baryon
formulation of the effective field theory. For the latter, we also work out
explicitly all 1/m corrections at fourth order. We display all relevant
relations needed to find the linearly independent terms.Comment: 30 pp, LaTeX2e, coefficients of three third order 1/m^2 corrections
proportional to F_{\mu\nu}^+ corrected in eq.(3.8) and table