The glass armonica is a musical instrument invented by Benjamin Franklin in 1761. It works on the wet finger around the wine glass idea. Very popular in Europe, even Mozart and Beethoven composed for it. But almost immediately it developed an uncanny reputation for both Good and for Ill: Franz Mesmer used his armonica to 'mesmerize' his patients, while others said it caused nervous disorders and even convulsions in your pets. Yet, glass music in general and the glass armonica in particular also seem to have attracted an inordinate number of geniuses great and small who were gripped by the 'divine madness' which is the source of all great Science and Art. In The Glass Armonica: the Music and the Madness we meet these 'divine lunatics', and discover the extraordinary way their lives were touched by glass music, as well as their own equally extraordinary contributions to its ongoing story, beginning with the Kama Sutra through the demise of glass music in the mid-19th century.