Steven Pinker's latest, as reviewed in Focus
a while back, and c+p-d from my Play.com review to save time...
The notion that we are gradually becoming nicer to one another seems counterintuitive, with wars in Iraq and Afghanistan, rioting in the streets of many cities last summer and the Stephen Lawrence affair occupying headlines.
The book is very long, and in fairness needs to be in order to present the masses of evidence that its main theme requires, and to elaborate upon any limitations or inconsistencies that may exist. I've not quite finished it yet (so forgive the slightly premature review), but I find Pinker to be a plausible and balanced man. Clearly there's no way a lay person can digest all the source material, so we have to make our judgements about what we read at a less rational level. I understand that this is what I am doing.
If his conclusions are right, it would be logical that the less frequent instances of violence will be noticed more and will appal us all the more. I hope (and see enough in the book to believe) that this is true.
Be warned though that some of the descriptions about acts which we were capable of in centuries past require something of a strong stomach. And the notion of halcyon days for previous generations is not one which survives closer examination.