Several of Beethoven's later compositions have the reputation of being chaotic to such a degree that they are difficult to play and to hear. This talk will address some of the most glaring instances of "extreme Beethoven," from the Hammerklavier Sonata, through the Credo of the Missa Solemnis, to the fractiously grandiose Grosse Fuge. We will listen for the material effects of extreme contrast and extreme concentration, as well as unrelieved dissonance (or what Charles Rosen calls "dissonance without pathos"), distortions of voice and subjectivity, and the deployment of the sonic "non plus ultra" as a dramatic design feature.