There are various methods for the analysis and design of bodies subject to static and dynamic loadings in structural and solid mechanics. Sensitivity analysis is concerned with the relationship between parameters, describing the structure under consideration and the function describing the response of that structure under loading conditions. This book addresses the finite element computational techniques typical of sensitivity analysis for solid mechanics systems with any nonlinearity. It is an attempt to combine theoretical modelling techniques with effective computer implementation: besides the theory many suitable finite element codes have been developed by the authors and used for computing examples discussed in the text.