It must be difficult to write a biography of someone such as Beethoven. Hasn't it all been written already? Is there really anything more to say? Apart from the occasional rediscovery of works and artefacts, there doesn't seem much scope for truly original thought or revelation.
Fortunately, I haven't read every previous text on Beethoven, so this problem does not matter. Lockwood's book is engaging and interesting. The book covers the biographical basics, though particularly in his later years this aspect becomes thinner and is overtaken by discussion of the music. There are two downsides to this. Firstly, his ambition stated in the preface is to provide a book that is balanced between Beethoven's life and works. Secondly, allegedly not to intimidate the reader, examples in musical score are omitted from the book and accessible on the publisher's website instead. The departure on the first point is bearable as it's a fine balancing act to tread. I suspect that the reasons for the second may be more financial: music scores are expensive to print because of the low density per page. Frankly, the depth of some of the musical discussion is sufficient that it should intimidate readers who can't read music scores anyway. Unfortunately, it is not typical to read the book whilst sat at the computer, so these web footnote examples are of very limited practical use.
During Radio 3's "Beethoven experience" last year I noted the number of minor and unremarkable works Beethoven wrote (in contrast, the "Bach Christmas" was much more consistent in its quality). Lockwood's book offers the explanation that Beethoven was a musical hoarder: nothing was ever completely discarded in case it became useful later on, and many trivial pieces were dashed off for friends or as compensatory freebies for the late arrival of promised works. This also explains the occasional out-of-sequence opus numbers given to works published much later than they were written and the many without opus number, which Beethoven regarded as lesser works.
When Lockwood discusses music with which I am familiar, what he has to say is interesting, but I admit that when the music is not familiar, it is easy to lose momentum. This is not a criticism of the book but should be considered as an incentive to become more familiar with Beethoven's string quartets and the Missa solemnis.