The idea for this book was conceived by the authors some time in 1988,
and a first outline of the manuscript was drawn up during a summer
school on mathematical physics held in Ravello in September 1988, where
all three of us were present as lecturers or organizers. The project was
in some sense inherited from our friend Marvin Shinbrot, who had planned
a book about recent progress for the Boltzmann equation, but, due to his
untimely death in 1987, never got to do it. When we drew up the first
outline, we could not anticipate how long the actual writing would
stretch out. Our ambitions were high: We wanted to cover the modern
mathematical theory of the Boltzmann equation, with rigorous proofs, in
a complete and readable volume. As the years progressed, we withdrew to
some degree from this first ambition- there was just too much material,
too scattered, sometimes incomplete, sometimes not rigor- ous enough.
However, in the writing process itself, the need for the book became
ever more apparent. The last twenty years have seen an amazing number of
significant results in the field, many of them published in incom- plete
form, sometimes in obscure places, and sometimes without technical
details. We made it our objective to collect these results, classify
them, and present them as best we could. The choice of topics remains,
of course, subjective.