Just thought that I'd mention some books that may be of interest. They are all by Charles Rosen.
Beethoven's Piano Sonatas: a Short Companion
This book has a commentary on each of the piano sonatas. Unlike many such companions, Mr. Rosen doesn't wax poetic, but rather points out salient features of the sonatas.
The best part, though, is Part 1: The Tradition
In this section he discusses many of the stylistic concepts and practices of the period. He talks about the formal principles of the period, Phrasing (and the meaning of slurs in classical practice vs. later romantic and 20th century thought), Tempo, Pedal and Trills, etc.
This section would be of value not only to the Beethoven piano performer but as a guide to piano performance of music of the classical period.
Includes CD of some examples
Yes, the plural is correct.
Have you ever noticed how they taught us the pattern for the Sonata form in theory class and then as soon as they show us the sonatas of Haydn, Mozart, and Beethoven we had to stand on our heads to explain all of the "exceptions". "They were geniuses so they could break the rules."
Rosen's claim is that the form that we were taught is a 19th century concept for 19th century purposes. The 3 masters didn't violate any supposed rules, but rather worked consistently within the classical vocabulary and language even as they expanded and enriched it.
The Classical Style
This one focuses on the various aspects and genres of the classical style through its 3 masters -- Haydn, Mozart, and Beethoven.
I admit, that moments are a bit of a trudge, not because of his writing, but the copious examples that he goes through in detail. It would be nice to have a CD of the examples. Though most are reduced to piano proportions, one doesn't always get the sound details, particularly for works for orchestra or opera. It does have a CD but just of the Hammerklavier.
That said, even as I skimmed through some sections that were less related to piano, I found many interesting insights.
I found each of these in the library, so you might be able to find them in yours.