The chemistry of inclusion compounds has a long history and is nowadays a subject of wide-ranging and intense study. With the awarding of the 1987 Nobel Prize in Chemistry to Donald J. Cram, Jean-Marie Lehn and Charles J. Pedersen for their fundamental work on 'host-guest' or 'supramolecular' systems, inclusion chemistry has come to the fore front in contemporary researches. Increasing varieties of novel inclusion compounds and new host molecules have been synthesized recently. The term 'crystal engineering' was coined by Schmidt to describe the rational design and control of molecular packing arrangements in the solid state, and the structural study of clathrates has contributed substantially