The photographs and the information that Gillis collected related to these photos are the core of this collection. All photographs are black and white, and are understood to have been collected from the previous owner for the express purpose of use in the book. Most of the photos shows people or scenes. Others are copy images, or photographs of other photos and illustrations from other sources, including sketches or maps.

Not all of the photos in the collection were used in the final version of the book as published. The master copy of the book, included with the collections, is annotated with a pencil number which corresponds to Gillis' original list of illustrations, and to the folder numbers in Boxes 3-4 of this collection.

For example, the illustration of the “Horse-drawn funeral procession on Quarry Ave....” pg. 30 top in the book, is Illustration #99 on Gillis list, and Box 3 Folder 99. The badges shown lower left on at same page in the book are illustration #197 on Gillis list, and Folder #197 of Box 4 of the photos.

The Photo Description Sheets in Box 2 of this collection are photocopies of the descriptive information which was recorded on the original envelops. The original envelops were acidic, and discarded after the photos were moved to acid free folders.