From a very broad literature on literacy, including the emergence of writing and early written documents, the following proved useful in defining the position stated in this book:

John Hladczuk, William Eller, and Sharon Hladczuk.
Literacy/Illiteracy in the World. A Bibliography. New York:
Greenwood Press, 1989.

David R. Olson, Nancy Torrance, and Angela Hildyard, editors.
Literacy, Language, and Learning: The Nature and Consequences of
Reading and Writing. New York: Cambridge University Press, 1985.

Robert Pattison. On Literacy: The Politics of the Word from Homer to the Age of Rock. New York: Oxford University Press, 1982.

Gerd Baumann, editor. The Written Word: Literacy in Transition.
New York: Oxford University Press, 1986.

National Advisory Council on Adult Education. Literacy Committee. Illiteracy in America: Extent, Causes and Suggested Solutions, 1986.

Susan B. Neuman. Literacy in the Television Age. The Myth of the
TV Effect. Norwood, NJ: Ablex, 1991.

Edward M. Jennings and Alan C. Purves, editors. Literate Systems and Individual Lives. Perspectives on Literacy and Schooling. Albany: SUNY Press, 1991.

Dr. Harald Haarman. Universalgeschichte der Schrift.
Frankfurt/Main: Campus Verlag, 1990.

David Diringer. The Alphabet. A Key to the History of Mankind. 3rd edition. New York: Funk & Wagnalls, 1968.