This book is the Bible of the mediatic electric age and it has to be read as such, that is to say with a grain of salt from time to time. Marshall McLuhan shows first of all that all inventions, all activities of man are extensions of something in his body: the hand, the arm, the foot, the eye, the nose, the ear, and of course the skin and the central nervous system. He then moves to showing that the mechanical age started with the wheel as the extension of man's feet and legs, when this wheel was plugged onto some mechanical source of energy, be it natural like stream-water, or be it man-made and artificial like the steam-engine or the internal-combustion-engine. But this very mechanical revolution produces the next stage since stream-water or steam are used to make a turbine turn, like a wheel, but this time to produce electricity. And we enter the electrical age, a revolution based on the virtualization of this energy that is no longer attached to a particular action or place: it can be used in hundreds of different tasks and everywhere due to its transportation. This leads to the next revolution: the birth of communication media, hot or cool, but all of them being the message itself. Radio, cinema, TV, camera, sound-recorder, etc..., and McLuhan could not know in 1964 the Internet revolution and virtual reality, the virtualization of all human activities. However, he feels and predicts the changes that were to come. Information can be transformed and transported by machines and the possession and use of knowledge become the real working power of a man. It means clearly that social projects are no longer collective but based on individual potential, competence and activity. We thus can shift from collective nationalism (the explosion of humanity into opposed and distinct fundamentally irrational though logical-looking groups corresponding to the mechanical revolution) to universal globalization that makes all human beings equal, necessary, useful in the knowledge they possess and can move or use. This vision of globalization has little to do with Marx's dream of communism and Marshall McLuhan is perfectly aware that this globalization is a process containing - and finding its inner energy from - contradictions, such as the two trends towards detribilization and retribilization. But Marshall McLuhan is best-known for his approach of radio-cinema-TV. He sees very well the differences between them. Radio, the hot extension of one sense, hearing. Cinema, the hot extension of two senses, hearing and sight. TV, the cool extension of all senses (synesthesia) that requires total and tactile contact. But here he is led astray by his natural optimism. He considers TV leads to participation, which is true, but he does not qualify it properly because he does not see the participation radio and cinema require. With TV the individual projects himself into the medium with which he merges in total osmosis. It is purely sensual or sensuous, hence entirely passive mentally. With radio and cinema the projection is that of the show onto the mental black and blank screen of the mind for this mind to compensate all the missing elements (all but sound with radio, quite a lot with cinema, and in both cases the necessary mind as the Buddhist sixth sense to provide all the connections necessary for full understanding). Here the participation is first of all mental and even intellectual. A hot media thus mobilizes the mind. A cool media mobilizes the sensual and sensuous senses, if not only sensations. This leads to the unanswered question about the Internet and Virtual Reality. A new synesthetic medium that is hot because it requires the user to take in his own hands all the parameters including his own definition: and sure enough he can assume one chosen persona or several chosen personae, just as much as he may have to pare off or negotiate the persona or personae that the personae he may meet there may project onto him. That's the hot medium of today already and tomorrow. The next stage is still pure science-fiction.
Dr Jacques COULARDEAU, University of Paris Dauphine & University of Paris I Pantheon Sorbonne.