Zeolites, with their crystalline microporous structure, are cordial hosts to a wide variety of guests. Traditional absorption techniques, as well as X-ray diffraction and spectroscopic techniques, have contributed to a better understanding of the nature of the host materials' characteristic cavities, cages and channels. The same techniques, coupled with powerful computational methods, have given new insights into the interactions of guest molecules with their hosts. In turn, this has led to new developments in the direction of structure during zeolite synthesis as well as potentially new...