The Virtual Paper software centers around the notion of a document, which
generally corresponds to a single paper, report, or book. A document is
stored as a single file, in a format that we call a "Lectern document". The
application "BuildLectern" constructs these documents, and "Lectern" lets you
view them on your computer. 

A Lectern document contains images of each page of the document (at several
scales), text for the pages (for searching, not for viewing), and global
information about the document (such as a copy of a PostScript version of the
document, if available). 

A Lectern document has a fairly simple internal structure. There's an
internal directory, and a set of components. The components each contain the
bytes for some part of the overall document: a single page image at a
particular scale, or the text for a single page, or the PostScript that was
used to create the document. 

BuildLectern generates a single Lectern document. Its input can be a
PostScript file, or parts of previously built Lectern documents. Or its
input can be original raster-based images (such as a set of TIFF files),
typically at a moderate resolution such as 300 DPI. Finally, BuildLectern's
input can be a combination of all of these. 

For more information, please see:

	http://www.research.digital.com:80/SRC/virtualpaper