Live recordings of all five cello sonatas, with some nice extras, by Jacqueline du Pré and Daniel Barenboim. I wrote about Du Pré and the early end of her career in my article about the Haydn concerto’s.
Sonatas are an important genre in the chamber music. In very different instrumentations, but always with the same structure: the sonata form. A strong theme introduces the work, followed by a second, less important one. The themes are then developed, varied on, and the sonata ends with a recapitulation of the starting theme. The sonata form was present not only in chamber music, but was used everywhere in the romantic period.