In the past decades now a famous class of evolution equations has been discovered and intensively studied, a class including the nowadays celebrated Korteweg-de Vries equation, sine-Gordon equation, nonlinear Schr] odinger equation, etc. The equations from this class are known also as the soliton equations or equations solvable by the so- called Inverse Scattering Tra- form Method. They possess a number of interesting properties, probably the most interesting from the geometric point of view of being that most of them are Liouville integrable Hamiltonian systems. Because of the importance of the soliton equations, a dozen monographs have been devoted to them. H- ever, the great variety of approaches to the soliton equations has led to the paradoxical situation that specialists in the same ?eld sometimes understand eachotherwithdi?culties. Wediscovereditourselvesseveralyearsagoduring a number of discussions the three of us had. Even though by friendship binds us, we could not collaborate as well as we wanted to, since our individual approach to the ?eld of integrable systems (?nite and in?nite dimensional) is quite di?erent. We have become aware that things natural in one approach are di?cult to understand for people using other approaches, though the - jects are the same, in our case - the Recursion (generating) Operators and theirapplicationsto?niteandin?nitedimensional(notnecessarilyintegrable) Hamiltonian systems."

In the past decades now a famous class of evolution equations has been discovered and intensively studied, a class including the nowadays celebrated Korteweg-de Vries equation, sine-Gordon equation, nonlinear Schr] odinger equation, etc. The equations from this class are known also as the soliton equations or equations solvable by the so- called Inverse Scattering Tra- form Method. They possess a number of interesting properties, probably the most interesting from the geometric point of view of being that most of them are Liouville integrable Hamiltonian systems. Because of the importance of the soliton equations, a dozen monographs have been devoted to them. H- ever, the great variety of approaches to the soliton equations has led to the paradoxical situation that specialists in the same ?eld sometimes understand eachotherwithdi?culties. Wediscovereditourselvesseveralyearsagoduring a number of discussions the three of us had. Even though by friendship binds us, we could not collaborate as well as we wanted to, since our individual approach to the ?eld of integrable systems (?nite and in?nite dimensional) is quite di?erent. We have become aware that things natural in one approach are di?cult to understand for people using other approaches, though the - jects are the same, in our case - the Recursion (generating) Operators and theirapplicationsto?niteandin?nitedimensional(notnecessarilyintegrable) Hamiltonian systems."

This is both a textbook and a monograph. It is partially based on a two-semester course, held by the author for third-year students in physics and mathematics at the University of Salerno, on analytical mechanics, differential geometry, symplectic manifolds and integrable systems.As a textbook, it provides a systematic and self-consistent formulation of Hamiltonian dynamics both in a rigorous coordinate language and in the modern language of differential geometry. It also presents powerful mathematical methods of theoretical physics, especially in gauge theories and general relativity.As a monograph, the book deals with the advanced research topic of completely integrable dynamics, with both finitely and infinitely many degrees of freedom, including geometrical structures of solitonic wave equations.