The ancient nations where those people lived have disappeared. Of all the ancient people who lived in the Fertile Crescent, only the Hebrews have kept their identity as a people. Today they are known as Jews, after the Kingdom of Judah, where they lived long ago. https://spirituality.knoji.com/facts-about-the-hebrews/ The book of Hebrews was written by an unknown author. Hebrews is also referred to as the "Faith Chapter" in the Bible. http://allchristiannews.com/the-book-of-hebrews-what-you-may-not-know-about-the-masterpiece/