Since the first edition of "Principles of Packaging Development" was published, the packaging industry has undergone many profound changes. These have included the virtual elimination of cellophane and its replacement with oriented polypropylene as a carton overwrap, fluid milk in blow-molded HDPE bottles, PET beverage bottles, cookie bags and cartons lined with polyolefin coextrusions instead of waxed glassine, and bread in reclosable polyolefin and coextruded film bags. New phrases have also worked their way into the lexicon of the practic- ing packaging technologist, such as "child...