A lipogram is a span of text in which a particular letter or group of letters is avoided. Composition of very long lipograms is a popular pastime among logologists - indeed, some particularly dedicated constraint writers have produced entire novels which do not use the letter E.
"Unigraphic Lipogrammatic Windows: A Survey,"
Word Ways: Vol. 47
, Article 16.
Available at: http://digitalcommons.butler.edu/wordways/vol47/iss2/16