Model order reduction based on proper orthogonal decomposition: Model reduction: extracting relevant information.- Interpolation of reduced basis: a geometrical approach.- POD for non-linear models.- Conclusions.- PGD for solving multidimensional and parametric models: Introduction.- Separated representations.- Advanced topics.- Models defined in plate and shell geometries.- Computational vademecums.- PGD in linear and nonlinear Computational Solid Mechanics: Introduction.- PGD -Verification for linear problems (elliptic and parabolic).- PGD for time dependent nonlinear problems (monoscale and multiscale problems).- Reduced basis approximation and error estimation for parameterized elliptic partial differential equations and applications: Introduction and motivation.- Parameterized problems.- High order and reduced order models with reduced basis method: greedy algorithm and a posteriori error estimation.- Applications.- Conclusion.