책을 보다 and 책을 읽다 means nearly the same. Literally, '보다' = to see, to look, to observe, to watch etc. '읽다 ' = to read, to study, etc. But, we use both expressions at the same situation. 지켜보다 = to look at, to see, to observe, to watch etc, especially with care. 지켜요? = to keep a rule, to protect something/someone, to keep something/someone etc.