Philipp Joseph Frick was an organist, composer and noted performer on the glass armonica, who captivated audiences all over Europe in the eighteenth century, from Russia to London. As he described himself, "the Writer was (formerly) obliged to travel through the greatest part of Europe, and thus became known with his musical instrument Harmonica, almost to every Monarch and Individual."He also composed and published works for piano/harpsichord and other instruments, and several books on music theoryA review mentions that he played one of his own compositions, so apparently he composed for it, alas none have apparently survived.He also tried to add a keyboard to the armonica.In 1797—a year before his death—he published his mystical religious magnum opus called The True Knowledge of God and Man; of the Great Sabbath on Earth; and of the Restoration of All Things; With some Essential Remarks on the Duty we owe to our Creator, generally now referred to (when referred to at all) as simply The True Knowledge.