If you're taking a course in Beethoven, at a graduate level, this is pretty important required reading. It's comprehensive, and along with the Solomon book, and the Kerman/Tyson offering in the small New Grove edition, you cover a lot of info. It's well-written and doesn't get too lagubrious, in spite of it being translated from the German. I found the subject matter spurred me on anyway. Even though the work first appeared in 1921, a lot of the information remains accurate, and one gains also some insight into what a remarkable historian Thayer was.