It's worth reading some reviews in Amazon. For instance:
* 3 stars by "Beethoven Over All" http://www.amazon.com/review/R3PHM8XHYS4DAL/ref=cm_cr_rdp_perm
"There is a lot of information that makes this short study interesting but I ultimately did not find this book very satisfying. A danger in writing a biography is that the author can fall under the spell of his subject and cease to be objective. I found this to be the case with Mr. Morris especially in his first chapter where he addresses his subject as "Ludwig" and seems eager to explain his life rather than objectively relate events."
* 1 star by W. R. Shindle http://www.amazon.com/review/R2VANSFYO2AMOH/ref=cm_cr_rdp_perm
"It did not take me long before before I realized that Morris relied too much on the writings of the Sterbas, and accepted without questioning some of the more controversial aspects in the writings of Maynard Solomon."