I wrote Zuke 'Em to help players searching for an opening, or those who already played the C-Z. Consistent with my desire to make this the most helpful book possible, I welcome any comments or questions from readers. Simply email me.
You can also visit the Zuke-Dukes Forum dedicated to the opening and the book.
An opening book should be like software: once you buy it, the author should offer free updates as new ideas are found. Here are some updates and other articles that might be useful to you:
Major Update: New Idea in the mainline! (Chessville Article)
More Analysis on the Hybrid Zukertort (At the Kenilworthian)