The papers collected in this volume, presented at the workshop on "Nonlinear Problems in Engineering", held in ENEA Rome (Italy) from 6 – 7 May 1991, and sponsored by ENEA, report nonlinear problems of prevailing engineering interest. Both nonlinear static and dynamic topics are dealt with; in particular, plastic behavior of materials, elastic-plastic models, fracture mechanics, geophysical prospecting, theory of nonlinear control, mixing models for chemical reactors, nonlinear responses of structures, rotor dynamics, and impact loads on structures.