May 9, 2008 lecture by Dan Morris for the Stanford University Human Computer Interaction Seminar (CS547).  MySong is a system that automatically chooses chords to accompany a vocal melody. A user with no musical experience can create a song with instrumental accompaniment just by singing into a microphone, and can experiment with different styles and chord patterns using interactions designed to be intuitive to non-musicians. Dan Morris describes how MySong works, discusses results from a recent usability study, and shows lots of audio examples to demonstrate that non-musicians are in fact able to use this system as a powerful creative tool.