I used to teach a course at Northwestern University on Orality, Literacy, and Cybercy. I wish that this book had been written sooner so that I might have included in my course on the history of communications. Marshall Poe breaks the history into five eras: the eras of orality, writing, printing, audio-visual, and computers. Of course no medium drives out earlier media, but instead we accumulate different ways of communicating. As earlier writers such as Elizabeth Eisenstein, Harold Innis, Marshall McLuhan, Walter Ong, and Neil Postman have made clear, each new medium has profound effects on society.
Poe analyzes each of the five media in terms of eight critical characteristics: accessibility, privacy, fidelity, volume, velocity, range, persistence, and searchability. He looks at these from the point of view of both the sender and receiver. Most importantly he analyzes effect of these characteristics on social practices and cultural values. This is a grand theory about the effects of different media, and everyone who wants to understand how media affect society will find this book both well written and quite revealing.