As our title suggests, there are two aspects in the subject of this
book. The first is the mathematical investigation of the dynamics of
infinite systems of in- teracting particles and the description of the
time evolution of their states. The second is the rigorous derivation of
kinetic equations starting from the results of the aforementioned
investigation. As is well known, statistical mechanics started in the
last century with some papers written by Maxwell and Boltzmann. Although
some of their statements seemed statistically obvious, we must prove
that they do not contradict what me- chanics predicts. In some cases, in
particular for equilibrium states, it turns out that mechanics easily
provides the required justification. However things are not so easy, if
we take a step forward and consider a gas is not in equilibrium, as is,
e.g., the case for air around a flying vehicle. Questions of this kind
have been asked since the dawn of the kinetic theory of gases,
especially when certain results appeared to lead to paradoxical conclu-
sions. Today this matter is rather well understood and a rigorous
kinetic theory is emerging. The importance of these developments stems
not only from the need of providing a careful foundation of such a basic
physical theory, but also to exhibit a prototype of a mathematical
construct central to the theory of non-equilibrium phenomena of
macroscopic size.