Throughout most of human history, the total amount of usable resources people had at their disposal was consistently low – the contemporary equivalent of between $1 and $3 per person per day. One cannot do much with that. Could you live today on, say, $3 per day? To furnish you with all your needs – from food, clothing, and shelter, to music, coffee, graduate school, that new pair of shoes, and the next iPhone? You might be able to survive, but only barely; you would likely have to give up an enormous number of the things you enjoy in life today – and you had better hope you do not get sick or break a bone. The proportion of human beings living at that historical low level, however, is today lower than it has ever been.