If you are in search of more information about your building and its previous residents, try the Aurora Historical Society. They also have a complete set of city directories and have various other historical sources. Some of the most helpful items include:
Sanborn Fire Insurance Maps - These maps were published for communities all across the United States beginning in 1867. They are very detailed and can help you determine the size, shape, and building and building material of a building. Sanborn Maps for Aurora were conducted in 1885, 1897, 1907, and 1957.
Probate Inventories - Probates can be helpful to see descriptions of property, who inherited property, and how much it was worth at that time. An index for the probates can also be found at the Aurora Public Library.
Aerial Maps - Drawn in 1867 and 1882, these maps show a birds-eye view of Aurora. They can also be found online via the Library of Congress. Conduct a search for Aurora, Illinois and you will find the 1867 and 1882 maps and a zoom capability.