From Wikipedia:

Neil Postman (March 8, 1931 – October 5, 2003) was an American author, media theorist and cultural critic, who is best known by the general public for his 1985 book about television, Amusing Ourselves to Death. For more than forty years, he was associated with New York University. Postman was a humanist, who believed that “new technology can never substitute for human values.”

What was he like? You can get an idea from this brief interview

Mr. Postman worked closely with Marshall McLuhan

In 1977, Marshall McLuhan defined media ecology as:

…means arranging various media to help each other so they won’t cancel each other out, to buttress one medium with another. You might say, for example, that radio is a bigger help to literacy than television, but television might be a very wonderful aid to teaching languages. And so you can do some things on some media that you cannot do on others. And, therefore, if you watch the whole field, you can prevent this waste that comes by one canceling the other out.

Inspired by McLuhan, Neil Postman founded the Program in Media Ecology at New York University in 1971. He described it as:

Media ecology looks into the matter of how media of communication affect human perception, understanding, feeling, and value; and how our interaction with media facilitates or impedes our chances of survival. The word ecology implies the study of environments: their structure, content, and impact on people.