Who Was Emer Vattel (1714-1767)?

The American moralist may know Emer Vattel as the source of that storied line in the United States Declaration of Independence: "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness .” Vattel's influence came primarily from his magnum opus , The Law of Nations . Who was he, and what was it about his ideas that inspired a global philosophical crusade which took as its object the search for the meaning of life ? What does Vattelian happiness , and what about that conception is applicable in the modern world?