One recent book that has made a huge impression on me (and to which I may devote some serious blogging at some point) is Steven Pinker's The Better Angels of Our Nature, which is about the world-historic decline in violence over much of human history, as hard as that may be to believe.
Pinker kicks over an idol in that book which was long overdue for smashing: the idea that we were nicer 100,000 or so years ago than we are today. That bogus myth was a mainstay of bad social science for a good while but it no longer holds up.
According to that bogus myth, early humans were peaceful and holistic (if not dietary vegans) while modern humans were warlike and violent.Short version: good then, bad now.
A closer examination of the evidence of history, archaeology, and evolutionary science suggests that Hobbes was closer to being right than those with a more optimistic view of "original" human nature. For most early humans, life probably really was "nasty, brutish, and short."
Undoubtedly many more individuals died violently in the 20th century than in ancient hunter/gatherer times. But, taken as a percentage of the population, the rate of violent deaths may actually have declined.
In other words, sad as it may seem, we may actually be getting nicer.