Hard Ball Systems and the Lorentz Gas are fundamental models arising in
the theory of Hamiltonian dynamical systems. Moreover, in these models,
some key laws of statistical physics can also be tested or even
established by mathematically rigorous tools. The mathematical methods
are most beautiful but sometimes quite involved. This collection of
surveys written by leading researchers of the fields - mathematicians,
physicists or mathematical physicists - treat both mathematically
rigourous results, and evolving physical theories where the methods are
analytic or computational. Some basic topics: hyperbolicity and
ergodicity, correlation decay, Lyapunov exponents, Kolmogorov-Sinai
entropy, entropy production, irreversibility. This collection is a
unique introduction into the subject for graduate students, postdocs or
researchers - in both mathematics and physics - who want to start
working in the field.