Nice overview of McLuhan's life.

"Usually McLuhan used hot to describe media that are rich in information and require little participation on the part of the user. Radio is hot because the sound of the human voice is magnified and human speech is standardized and clarified, reducing the amount of interpretation required to understand it. The recipient of the radio broadcast receives a rich information stream that passes through the ears to the brain.

In contrast, the television watcher is highly involved, because the low-resolution TV monitor, with its mosaic screen, requires greater mental participation. TV encourages ironic commentary from viewers, who are constantly being challenged to pull the picture together in their mind's eye. Television produced the remote control and channel surfing, which make this sort of participation obvious. Few listeners use remote controls with radios, and channel surfing on the radio is associated only with the most low-fi radio environment - the automobile.

Hot media deliver more information because they have taken a single sense, such as sight, and magnified and abstracted it to a state of optimum efficiency. Printed books are hotter than illuminated manuscripts because printed books are uniform and repeatable; once a person has mastered the code and become an experienced reader, there is nothing in the book to distract from the direct and rapid transfer of data. In an illuminated manuscript, the text is presented in unique visual style which the reader must attentively contemplate."