A typical modern score for Haydn has a boatload of editorial suggestions for dynamics, staccato, tenuto, etc. I'm sure these editors know more than I do (that's not hard), but I'd like to know more about the basis of this. After "An Essay on the True Art of Playing Keyboard Instruments", what other reading is out there?
I can recommend "Performance Practices in Classic Piano Music" by Sandra Rosenblum. This book deals with how piano music was played in the classical period--Mozart, Haydn, early Beethoven, Clementi, etc. The author has synthesized treatises from that era with illustrations from the music, and given her own opinions on various problems of interpretation. I found the book very useful in giving me some background in how to make my own decisions on how to play a particular passage or piece.
- The Classical Style: Haydn, Mozart, Beethoven, by Charles Rosen (2nd ed., 1998, W. W. Norton) is very highly regarded. Worldcat link.
A greatly expanded edition of the National Book Award-winning masterpiece by a world-class pianist and writer on music. This outstanding book treating the three most beloved composers of the Vienna School is basic to any study of Classical-era music. Drawing on his rich experience and intimate familiarity with the works of these giants, Charles Rosen presents his keen insights in clear and persuasive language. For this expanded edition, now available in paperback for the first time, Rosen has provided a new, 64-page chapter on the later years of Beethoven and the musical conventions he inherited from Haydn and Mozart. The author has also written an extensive new preface in which he responds to other writers who have commented on his ideas. (Amazon)
- Classical and Romantic Performance Practice: 1750 - 1900, by Clive Brown (2004, Oxford University Press) focuses specifically on how notations would have been understood by performers of the time. Worldcat link.
The past ten years have seen a rapidly growing interest in performing and recording Classical and Romantic music with period instruments; yet the relationship of composers' notation to performing practices during that period has received only sporadic attention from scholars, and many aspects of composers' intentions have remained uncertain. Brown here identifies areas in which musical notation conveyed rather different messages to the musicians for whom it was written than it does to modern performers, and seeks to look beyond the notation to understand how composers might have expected to hear their music realized in performance. There is ample evidence to demonstrate that, in many respects, the sound worlds in which Mozart, Beethoven, Wagner, and Brahms created their music were more radically different from ours than is generally assumed. (Amazon)