This document compares characteristics of poor and rich countries to determine the key difference between them. It argues that the difference is not related to a country's age, natural resources, or intellectual abilities, but rather the attitudes and principles followed by its people. The principles of ethics, integrity, responsibility, respect for laws and others, work ethic, savings, punctuality that are predominantly followed in rich countries are not widely adopted in most poor countries. Adopting these attitudes, says the author, is necessary for countries to develop and prosper.