Add document information to your PDF, even without using Acrobat.

Traditional metadata includes things such as your document's title, authors, and ISBN. But you can add anything you want, such as the document's revision number, category, internal ID, or expiration date. PDF can store this information in two different ways: using the PDF's Info dictionary or using an embedded Extensible Metadata Platform (XMP) stream. When you change the PDF's title, authors, subject, or keywords using Acrobat, it updates both of these resources. Acrobat 6 also enables you to export or import PDF XMP datafiles. Visit http://www.adobe.com/products/xmp/ to learn about Adobe's XMP.

In Acrobat 6, view and update metadata by selecting File >Document Properties . . . >Description or Advanced >Document Metadata . . . . In Acrobat 5, select File >Document Properties >Summary. Save your PDF after making changes to the metadata.

Pdftk currently reads and writes only the metadata in a PDF's Info dictionary. However, it does not restrict you to just the title, authors, subject, and keywords. This solves the basic problem of embedding information into a PDF document; pdftk allows you to add custom metadata fields to PDF as needed. pdftk is free software.

Xpdf's (http://www.foolabs.com/xpdf/) pdfinfo reports a PDF's Info dictionary contents, its XMP stream, and other document data. pdfinfo is free software