Kenny Centazzo is the author of the book "Tower of Druids". In Cabin Fever, Greg explains that he got the book signed by the author last year, which was Kenny Centazzo. In the present, Greg figured out that a first-edition signed copy "Tower of Druids" is worth 40 dollars, enough to make Gregory's Little Friend in Net Kritterz a jacuzzi. So Greg wants to sell it, but Susan said she waited a long time to get that book signed by the author, so he might regret it. Plus, Susan said that when he has kids, they would be mad because that Greg sold it. So now, Greg is clearly turned off to having kids as mentioned by him, rather spending his money on vacations and luxuries like Uncle Charlie.
So, later, Greg goes to the guy that works at the forgery to sell it, but he said that it wasn't worth any cash. Then, he showed Greg a catalog with Kenny Centazzo's autograph, and Greg found out that it's a fake signature. Greg figures out that Susan signed the book because she couldn't wait in the line for a long time, so she signed it on her own and Greg got angry and Susan felt a little guilty.
At the end of the book, one of Greg's Christmas presents was "Tower of Druids" and Susan said she got it signed by the real author. Susan said it took 3 hours, but Susan was happy she could do it for him. However, Kenny spelled Greg's name wrong, he spelled it "Craig", so Greg hopefully he can find a rich guy named Craig who is really into graphic novels and sell it to him for a pile of cash. This is the only part of the book where a picture of Kenny is.