Four-dimensional integrable Hamiltonian systems with simple singular points (topological aspects)

General results of the theory of Hamiltonian systems Linear theory and classification of singular orbits IHVF and Poisson actions of Morse type Center-center type singular points of PA and elliptic singular points of IHVF Saddle-center type singular points Saddle type singular points Saddle-focus type singular points Realization Normal forms of quadratic Hamilton functions and their centralizers in $sp(4,{\mathbb R})$ The gradient system on $M$ compatible with the Hamiltonian Bibliography.