Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. XML Professional Publisher (XPP) is an automated XML based publishing system that was developed out of a proprietary typesetting system. XPP is a standards-based, content formatting and publishing application for the automatic composition, transformation, and rendering of XML, SGML or tagged ACII content into high-quality output into PostScript and PDF format. It holds the XML or SGML in its native format and it is able to re-export the data after paper pagination, even if corrections have been made in XPP. The software is used worldwide to produce a wide variety of publications including Technical Documentation, Scientific, Medical Journals (STM) Directory, Dictionary and Legal loose-leaf publishing. XPP was originally, in the early 1980s, a proprietary system which included the software and hardware.