Convex Analysis on Phase Space.- Legendre-Fenchel Duality on Phase Space.- Self-dual Lagrangians on Phase Space.- Skew-Adjoint Operators and Self-dual Lagrangians.- Self-dual Vector Fields and Their Calculus.- Completely Self-Dual Systems and their Lagrangians.- Variational Principles for Completely Self-dual Functionals.- Semigroups of Contractions Associated to Self-dual Lagrangians.- Iteration of Self-dual Lagrangians and Multiparameter Evolutions.- Direct Sum of Completely Self-dual Functionals.- Semilinear Evolution Equations with Self-dual Boundary Conditions.- Self-Dual Systems and their Antisymmetric Hamiltonians.- The Class of Antisymmetric Hamiltonians.- Variational Principles for Self-dual Functionals and First Applications.- The Role of the Co-Hamiltonian in Self-dual Variational Problems.- Direct Sum of Self-dual Functionals and Hamiltonian Systems.- Superposition of Interacting Self-dual Functionals.- Perturbations of Self-Dual Systems.- Hamiltonian Systems of Partial Differential Equations.- The Self-dual Palais-Smale Condition for Noncoercive Functionals.- Navier-Stokes and other Self-dual Nonlinear Evolutions.