On the positive side, they can be powerful agents of change for better health.

"I was always an independent man, never in the hands of any very powerful agent," he said.

If I don't have the strongest, most powerful agents, customers will go to someone else.

He is now on the road to becoming the most powerful agent in Hollywood.

I am a science educator interested in television as a powerful educational agent.

"It's a family series that hasn't been on in a long time," my partner told the powerful agent who had secured our meeting.

But movies were only the most powerful agent of the new.

I'd established my name as a lawyer, so I had access to the most powerful literary agent, no questions asked.

The students are the ones who become the powerful agents of social change.

The upside of despair is that it can be a powerful agent for change.