It's been a while since I picked up a new (to me) book and read it cover to cover, but last week I started A Short History of Nearly Everything, by Bill Bryson. It covers the quest to figure out the nature and the age of the universe, and all the different sciences that had to be developed over the past few centuries to answer our questions about our place in it (from Seismology to Astronomy, and pretty much every scientific discipline in between). Fascinating stuff!
Also, just finished The Monkey Wrench Gang, by Ed Abbey, for the second time. Fun read!