Search Library for a book, and search text inside a book are both things we would like to implement. The former is somewhat less complicated to develop, the latter however is rather complex.
One of the big reasons is that we would need to use a custom webkit, as the one supplied by Apple does not provide search capabilities for HTML. If we did add this then we would still need to load each chapter to search it, which would be slow, therefore we would want to create a search index for a book, and that adds another level of complexity to things.
In addition, a custom webkit adds quite a bit of size to an application, and with Apple
s previous 20MB limit for app downloads over a cellular data connection, it would have taken the app over that size. Now the limit is 50MB, it does leave some room.