Sunday is the anniversary of something that undoubtedly has changed your life.

Whether for good or for bad is a question only you can answer.

On this day in 1973 — on April 3 of that year — a man did something no one had ever done before…The man’s name was Martin Cooper. He was 44 at the time. He made a cell phone call.

The world’s first. At least the first public one; the cell phone had been tested in the lab, but never tried in the real world.

“As I walked down the street while talking on the phone,” Cooper once told an interviewer, “sophisticated New Yorkers gaped at the sight of someone actually moving around while making a phone call…”

Cooper, who was the general manager of Motorola’s communications systems division, had the idea that people didn’t want to be tethered to a stationary telephone, even if the phone could ride along with them in their car. He thought that the phone should be so portable that it could go anywhere they went.

As he explained it in a later interview: “People want to talk to other people — not a house, or an office, or a car. Given a choice, people will demand the freedom to communicate wherever they are, unfettered by the infamous copper wire…”

When Martin Cooper made that first cell phone call, he did not make it to another cell phone. People didn’t have them yet — who could he call?

No, he made the cell phone call to a land line — specifically, to the land line of his chief competitor at Bell Labs.

Motorola had beaten Bell to become the first company to make personal cell phones work. Cooper, you might say, rubbed it in. Think how the Bell Labs research engineer must have felt when he heard Cooper calling him from the noisy streets of Manhattan.

He’s still alive, by the way. He’s 82. He still works in the technology field.

Bravo! Some of my peers hope he doesn’t think of any else as disruptive.

Poisonally, I welcome change as critical as the communications revolution he kicked off. If your head is screwed on tight enough – you not only can deal with qualitative change, you should be able to turn it to your own advantage. If you wish to.