<?php
        $url = "edit_beginningcakephp.php?title=$title&author=$author&isbn=$isbn
                &year=$year&pages=$pages&price=$price";
            >?

  <input type="button" value="Edit Book" onclick="window.location.href='<?= $url ?>'">

$url = 'edit_beginningcakephp.php?title='.urlencode($title).'&author='.urlencode($author),'&isbn='.urlencode($isbn).'&year='.urlencode($year).'&pages='.urlencode($pages).'&price='.urlencode($price);