According to the "experts" whom I follow, both are "correct."  Both are perfect examples of the hypothetical conditional using the famous (terrifying?) subjunctive.  The book does NOT have endless pages, because it does NOT describe all the great things that you do. If we are at a party this moment, I might say "If Sue came, I would be astounded" or "If Sue were to come, I would be astounded."  (Sue hates parties.)  But careful: If Sue was at the party yesterday (a possibility), I certainly did not see her in the huge crowd. (P.S.  There are professional writers who might write: The book would have endless pages if it was...." and "If Sue were at the party yesterday...." Of course, I am no one to quarrel with them.)