Zeolites, with their crystalline microporous structures, are cordial
hosts to a wide variety of guests. However, it was the abrupt and
unexpected departure of one of these guests (water) from a host
(stilbite) on heating which led Cronstedt, in 1756, to coin the term
"zeolite" (from the Greek meaning "boiling stone") to describe this
material. Since that time, approximately 40 different
naturally-occurring zeolites have been discovered on earth. Recent
studies of meteorite compositions have shown that these guest-host
materials (e. g., sodalite) occur in other parts of the universe as
well. However, it wasn't until the twentieth century that synthetic
routes to zeolites and other non-aluminosilicate molecular sieves were
discovered. In addition, with the development of X-ray diffraction and
the various spectroscopies, better understanding of the nature of the
cavities, cages, and channels of these materials has led to the
industrial exploitation of their guest-host properties. The world of
zeolites has now expanded into a greater than 2 billion pound per year
business, with major applications in detergent formulations, catalysis,
and as adsorbents and desiccants. Their economic impact is difficult to
determine; however, the improvement in gasoline yields alone (from
catalytic cracking) must account for hundreds ofbillions ofdollars in
increased GDP. In this volume, we have brought together a sampling of
recent developments in various areas of guest-host or inclusion
chemistry in zeolites.