Mark Matthews has been making marbles for 35 years. Some-the banded lutzes and opaques, the latticino and solid and vane cores, the clambroths, onionskins, and peppermints-acknowledge their nineteenth century roots. Others-the precision air traps, the filigranas, the graals-employ techniques never before used in the making of marbles. Matthews makes marbles-spherical glass objects, to be sure, but glass spheres invested with a meaning, a significance, an aesthetic vision and purpose. In this sense, the marble is a means to an end, not an end in itself. Aesthetics-issues of form and color theory-combine with investigations into the physical and chemical properties of glass, which, in turn, engage social history and economic concerns, and all in the unlikely form of the marble, a crystalline sphere which, in Matthews' hands, produces its own kind of music.