For a while, it looked like book search was on an uninterrupted upward slope, improving in pretty much every way at a rapid pace - more books, more competitors, more search options.
Not so long ago (2007), Microsoft was saying they were going to go head to head with Google (Microsoft to Step up Book Search Tools
[webmasterworld.com]). 750,000 books indexed. Less than a year later, they were gone
No matter, Google's book search was by itself improving in every way. More books. The OCR seemed to be getting better.
Then a couple of weeks ago, I logged in and I can no longer restrict my search results to items in My Library
For me, this is the primary way I use Google Books. First search my library. If I don't find it, search more broadly. If I find something good in general search, add that book to my library. If you will, it's like manually controlled personalized search.
Why not start with the general search? Because I tend to use Google Books to research very specific topics and this lets me keep results focussed.
Anyway, I waited for the feature to come back, I searched Google help docs, I contacted Google support. At least for the time being, it's gone. Support promised that it would be back some day, but no timetable.
I'm hoping this will come back sooner rather than later. In the meantime, a powerful research tool that I've come to love is gone!
At this point, Google Books has almost no utility for me.