I have an addiction to used book stores, and usually waste a few hours on Saturday mornings getting my book fix. This weekend I found a book that was amazing. It's a bit old, but the subjects it deals with are still relevant.
Our brains are what makes us human. Without them we wouldn't be able to communicate or design the modern technologies we enjoy in modern civilization. This weekend I read Carl Sagan's The Dragon's of Eden. In this book he constructs the biological events that led to the evolution of the human mind. It's both fascinating and a little scary to realize how much of an accident we all are. Without random changes and natural selection the greatest works or art and the most complex engineering constructions would have never occurred.
The book talks about three different structures of the brain and how they evolved throughout time. These three parts: the R-complex, limbic system, and neocortex provide the functions needed for the mind. The latter provides the parts that make us distinctly human, and connect with the older parts that are left over from evolution.
For me, the fragility of our existence gives a good argument against war. In the book Sagan also makes a good case that being sufficiently evolved means that we should stop trying to find ways to kill each other. Instead, maybe we should try to work together... unfortunately this doesn't seem to be popular right now.
He also gives a good argument for a compromise on abortion using the information from previous chapters of the book.
This is one of the best popular science books i've read in a long time. Even though it might be old, (some of the computers he mentions are no longer used) I would still recommend it to every thinking person who likes to read.
It also won the Pulitzer Prize for general non-fiction in 1978.
There are good reviews on amazon
There is also a good review on scinet: http://www.scinet.cc/articles/doe/dragonsofeden.html
A good overview of the brain structures that are discussed in the book: