http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
95 pages : illustrations (some color) ; 21 cm.
Discusses codes, silent signals, invisible writing, and other ways to conceal messages.
by Shari Lewis ; Leo Benhke, consultant ; ill. by Helen McCarthy ; art direction by John Brogna.