THE ORIGINS OF THE Portable Document Format and the Adobe® Acrobat® product family date to early 1990. At that time, the PostScript® page description language was rapidly becoming the worldwide standard for the production of the printed page. PDF builds on the PostScript page description language by layering a document structure and interactive navigation features on PostScript’s under- lying imaging model, providing a convenient, efficient mechanism enabling doc- uments to be reliably viewed and printed anywhere.