It has been translated into eight languages and sold some 200,000 copies worldwide. In 2005, Postman's son Andrew reissued the book in a 20th anniversary edition. It is regarded as one of the most important texts of the Media Ecology school of criticism.
Postman argues that communication media inherently shape the conversations that can be carried out. To take an extreme example, it is not possible to conduct a discussion of philosophy using smoke signals; the conversation is too complex and long to be conducted over a medium of such low bandwidth. Postman in particular describes two forms of mass media, print and television, and the ways they influence the content carried across them.
Television as a medium is inherently assertionless; a video of an event makes no assertions whatsoever. It merely displays something that occurred. For example, an advertisement for McDonald's often says nothing about the burgers, their nutritional value, their cost or position in the market compared to the competition; instead, it shows happy, smiling children eating McDonald's burgers, followed by a happy clown.
A viewer can like or dislike a McDonald's advertisement, but he or she cannot accept or refute it, because there is nothing to accept or refute.
Postman distinguishes the Orwellian vision of the future, in which totalitarian governments seize individual rights, from the vision offered by Aldous Huxley in Brave New World, where people medicate themselves into bliss and voluntarily sacrifice their rights. Postman sees television's entertainment value as a "soma" for the contemporary world, and he sees contemporary mankind surrendering its rights in exchange for entertainment. (Note that there is no contradiction between an intentional "Orwellian" conspiracy using "Huxleyan" means, which is an argument advanced in the later book The Unreality Industry: the deliberate manufacturing of falsehood and what it is doing to our lives by Ian Mitroff and Warren Bennis [New York: Carol Pub. Group, 1989]. Postman evidently did not disagree, since he provided a blurb for this book.)
The essential premise of the book, which Postman extends to the rest of his argument(s), is that "form excludes the content," that is, a particular medium can only sustain a particular level of ideas. Rational argument, an integral component of print typography, cannot be conveyed through the medium of television because "its form excludes the content." Because of this shortcoming, politics and religion get diluted, and "news of the day" is turned into a commodity. The presentation most often de-emphasizes quality; all data becomes burdened to the far-reaching need for entertainment.
Postman objects to the presentation of television news as it is conveyed in the form of entertainment programming. He cites the inclusion of theme music, the interruption of commercials, and "talking hairdos" as the basis for his argument that televised news is presented so that it cannot readily be taken seriously. Postman further examines the differences between written speech, which he argues reached its prime in the early to mid-nineteenth century, and the forms of televisual communication, which rely mostly on visual images to "sell" lifestyles. He argues that politics has ceased to be about whatever ideas or solutions a particular candidate may possess, but instead whether or not they come across in a favorable way on television. Television, he notes, has introduced the phrase "now this", which indicates a complete absence of any connection between one topic and the next. Larry Gonick used this phrase to conclude his Cartoon Guide to (Non)Communication, instead of the traditional "the end".
Postman draws from the ideas of the media scholar Marshall McLuhan— slightly altering McLuhan's aphorism "the medium is the message" into "the medium is the metaphor"—to describe how oral, literate, and televisual cultures radically differ in how information is processed and prioritized. He also argues that different media are appropriate for different kinds of knowledge. The faculties necessary to sustain rational inquiry simply are not normally encouraged by televised viewing. Reading, a prime example cited by Postman, is a subject of intense intellectual involvement, at once interactive and dialectical, unlike television which limits involvement to passivity. Moreover, as television is programmed for maximum ratings, its content is determined by commercial feasibility, not critical acumen. Television in its present state, he says, cannot sustain any of the conditions needed for honest intellectual involvement and rational argument.
He also repeatedly states that the eighteenth century was the pinnacle for rational argument, truly being the Age of Reason. Only in the printed word, he states, could complicated truths be rationally conveyed. A striking example Postman gives: that the first fifteen U.S. presidents could probably have walked down the street without being recognized by the average citizen, yet all these men would have been quickly known by their written words. However, the reverse is true today. The names of presidents or even famous preachers, lawyers, and scientists call up visual images, typically television images, but few, if any, words come to mind. The few that do almost exclusively consist of carefully-chosen soundbites.