I hope that this listing of source materials referred to by the authors I consulted provides you with a first overview of relevant literature with respect to Beethoven's piano sonatas.; older titles might be either available in in well-equipped public libraries or in the antiquarian book trade, while newer titles might still be available through retail outlets.  

However, those readers who want to delve into this subject very seriously will find further selections via links from each of our sonata pages to relevant listings of the Beethoven Bibliography Database of the Ira Brilliant Centers for Beethoven Studies in San Jose, California, which we have already searched out for you and which can be accessed by clicking on each link.  

In our individual sonata pages' sections on comments of the musical contents of each sonata, you will find comments by authors such as Cooper, Kinderman and Solomon.  

After these comments, you will find a section that features comments by the German music critic Joachim Kaiser, from his work, "Beethovens 32 Klaviersonaten und ihre Interpreten". The purpose of Kaiser's book is already expressed in its German title.  He offers us an introduction to the topic, a brief overview of the musical content of each sonata, after which he discusses important insights into certain performance aspects, by the greatest pianists of the 20th century.  

In his book, Kaiser also mentions that his not "strictly scientific" overview is an attempt at lending a voice to important creative insights by these pianists.  

Kaiser's book was published in the mid-1970's.  That the time was ripe for letting such voices be heard can also be seen in the fact that the Beethoven researcher William Kinderman, whose book was published in 1995, also refers to Alfred Brendel's publications on the topic of Beethoven's piano works.  Some of Brendel's publications are also contained in the above list.  

All this excellent source material is only accessible to me by reading it.  Above and beyond that, I was also able to listen to Joachim Kaiser's excellent Radio show on Beethoven's works and their influence that was featured by the Classical Music Program of the Bavarian Radio in Munich.  

In them, I have gained a bit of insight into Kaiser's lively intellect.  For this reason, I have also tried to bring some of his ideas across in the English-language version of this section.  

The great pianist that I was able to hear, for myself and also meet and exchange a few friendly words with was Anton Kuerti, who initiated and organized the first Carl-Czerny Festival that took place in Edmonton from June 14 - 16, 2002, in Edmonton.  

As many Beethoven friends already know, Kuerti has recorded all of Beethoven's piano sonatas, as well as the Diabelli variations.  I have them here in an edition by  Analecta/Fleur de Lis, with comments Kuerti wrote, himself, and in our last section of each page, I will refer to those with respect to comment(s) from the viewpoint of an active pianist.   In his comments, Kuerti meets his goal of offering information that can be understood by everyone who can read English. 

As you can see, we are trying to offer you comments on the musical content of Beethoven's piano sonatas from various viewpoints, and we also provide you with the possibility to instantly move to the section you prefer to investigate further, should you have a predilection for a certain level of engagement. 

After this introduction with respect to the topic of comments on the musical content of Beethoven's Piano Sonatas offered here, I can refer you to the individual pages and wish you a great deal of reading enjoyment!