Although this Workbook is listed as one of the "Buy them both together!" packages, do NOT buy it this way. Textbook is 4th Edition, and the Workbook is the 3rd Edition.The deal I'm talking about is on this page:Horizons (with Audio CD).Didn't notice, or couldn't notice, doesn't matter, and now I have to stomach another $80 workbook, this time the right edition.Be forewarned.