What could be among the oldest surviving Chicago city records sit inside a special climate-controlled vault at the Illinois State Archives, largely indecipherable. These are volumes that survived the Great Chicago Fire 150 years ago. Today, they are stored in large wooden boxes in an extra-secure vault, where the temperature and humidity are controlled to prevent further deterioration. The archive is waiting for technology similar to what’s being used at the National Personnel Records Center in St. Louis to become more widely available.