Best-selling author and expert on leadership John C. Maxwell claims there is only one rule for business.How does a person judge what is ethical? Sometimes it's clear. You know Enron's leaders were in the wrong. But is it always easy to see where the line is in your life? What's the standard? And can it work in all situations? John C. Maxwell thinks it can. When the New York Times best-selling author, successful businessman, and former pastor was asked about his thoughts on business ethics, his response was, "There's no such thing.