Remember, that Christianity and Judaism share the Old Testament ...
In my opinion, it is incorrect to say that Christianity and Judaism share the Old Testament. The Jewish people have a collection of ancient writings recording myths, histories, codifications of law and religious beliefs. It is a large and extremely complex body of work.
The Christians usurped a portion of this large body of work, added an entirely different world view and a number of new ideas, mistranslated some sections, threw out some sections, added some sections, rearranged sections. They declared the Jewish original to be incorrect, corrupt, incomplete or intentionally misleading.
So I think it goes too far to say we share a book, let alone naming that "shared" book the "Old Testament".