Excerpted from THE SIXTH EXTINCTION: An Unnatural History by Elizabeth Kolbert. Published February 2014 by Henry Holt and Company. Copyright © 2014 by Elizabeth Kolbert. All rights reserved.The Icelandic Institute of Natural History occupies a new building on a lonely hillside outside Reykjavik. The building has a tilted roof and tilted glass walls and looks a bit like the prow of a ship. It was designed as a research facility, with no public access, which means that a special appointment is needed to see any of the specimens in the institute’s collection. These specimens, as I learned on the day of my own appointment, include: a stuffed tiger, a stuffed kangaroo, and a cabinet full of stuffed birds of paradise.The reason I’d arranged to visit the institute was to see its great auk. Iceland enjoys the dubious distinction of being the bird’s last known home, and the specimen I’d come to look at was killed somewhere in the country—no one is sure of the exact spot—in the...