The last "gotcha" is the cure time required when using PUR. Although books can be three-knife trimmed right after binding, it can take from 24 to 48 hours for PUR to reach full strength. Shipping the product "before it's time" risks failure of some, or all of the bind. In fact, there are many stories of books that had to be completely reprinted and rebound due to bind failures caused by many technical issues. So, while PUR has (in general) been a boon to book binding, you've got to do serious homework in order to be PUR proficient!