This one's a toughie. Not because there's is little to say but because there's too much. The subject of government has been one of constant debate and study for the entirety of truly recorded history, starting around the 8th century BC when people at last began to record for posterity the lives and beliefs of themselves and those around them. But those nearly three thousand years of discourse point to one oft overlooked definition of government: the eternal human project.
There's two ways people often think of government. The first is to not. To take not just government but our current form as a given and to unconsciously assume it's always been like this. The second is to think of government as something humanity sort of stumbled into, or perhaps was even trapped by. Neither is true as the idea of government, the idea of regulating ourselves to work more effectively together, goes back to the beginning of our evolution as a eusocial species. But, for three thousand years we've been experimenting and evolving ever more complex and sophisticated forms of doing this. Hopefully as our knowledge and methods improve we will continue to see the continuance of the trend we have seen in the Western world for the past couple centuries of increased freedom and happiness for ever larger swaths of the population. But, we must be vigilant, because evolution does not favor what is best but what survives. Throughout history there has evolved many governments that were and are fierce, predatory organisms. Red in tooth and claw. In the world today such governments are coming ever nearer to an endangered species, but those genes will always be in the pool of ideas from which governments are formed.