Trust is essential for establishing and maintaining mutually advantageous, even amicable, relationships in business or other cooperative social arrangements at interpersonal (micro), organizational (meso), and interorganizational network (macro) levels of analysis. A violation of trust will severely test and may end the relationship. There is an old saying that trust arrives on foot, but leaves on horseback. Herein lies the incentive to embed ethical considerations and practices into the management of business and other social relationships. One evolutionary biologist grounds the rise of human civilization in humankind’s trust-building capability for cooperating beyond the bond of kinship within the company of strangers.