Find iBooks Author
Right click on iBooks Author
Choose "Show package content"
Scroll all the way down to templates
Select "Textbook 04"
Click, drag to trash and empty trash
Open iBook author
It should be gone! If you are lucky enough to have Mac Laptops as our fifth graders do, I highly recommend giving iBook Author a try! Not only will your students have another publishing option, but you can share your work in the iBook Store, allowing students to expand their readership.