Summary: We present a system for solving a wide variety of inverse and optimization problems in solid mechanics. The system consists of a general purpose finite element method (FEM) analysis system “Elfen” and a shell which controls this system. The shell operates as a stand-alone programme, so the system is physically divided into two separated parts. The “optimization part”, which corresponds to the shell, possesses optimization and inverse problem solution algorithms. The “analysis part”, which corresponds to an FEM system, serves for the definition of the objective function to which these algorithms are applied. The shell has a user interface implemented in the form of file interpreter which imposes a great flexibility on the formulation of various optimization and inverse problems, including parameter identification in constitutive modelling, frictional contact problems and heat transfer. Concepts of the shell are discussed in detail.