This article draws together a range of perspectives on one of the supreme works in the piano repertoire, Beethoven’s Sonata no. 29, op. 106. Composed in extreme circumstances, it takes sonata form to the limit, while at the same time revealing a search for new ways forward. From its first appearance right up to the present day, its complexity has distanced it from the general public, and even from many performers. The main object of this study is to provide elements that enable us to understand what is, in stylistic terms, one of the composer’s most atypical pieces. For this purpose it examines biographical, contextual, and structural aspects of the work, as well as questions of interpretation on the basis of the various existing editions and of fifty-one performances, which confirm a widespread tradition of slow tempos, despite Beethoven’s precise and consistent indications.