Books of the same era, yes. But books from different eras, there are differences as people in the later era could not without great difficulty understand what in written in the oldest text. Chaucer's Canterbury tales is an example. Shakespeare's writing is easier to understand as it is in Early Modern English. Yes, some of his sentences and words are hard for many moderns to understand. For instance Shakespeare has Macbeth say, "Lay on McDuff." Most people today misunderstand this phrase. It is not an invitation to attack, but "after you," or I'll follow you.
Time change, words change, meaning changes, and some words disappear.