Craig Wright, teaching Yale's Listening to Music (MUSI 112), shows students how to hear bass lines as the key to harmonic progressions. He reviews chord formation and how chords create harmonic change, then demonstrates that the same three- and four-chord progressions run through both classical and popular music. Examples span Mozart, Beethoven, Rossini, and Wagner alongside Gene Chandler's Duke of Earl, the Beach Boys, Badly Drawn Boy, the Dave Matthews Band, and Justin Timberlake, with Wright playing passages at the piano to isolate the bass movement underneath each. The lecture builds from basic triads to full three-chord and four-chord patterns, tracing how a blues progression and a rock progression share the same underlying logic as a Beethoven sonata. Recorded in Fall 2008 as part of Yale's Listening to Music course, it works as a practical ear-training session as much as a history of harmony.