The William Ziegler Fonds consists predominantly of material gathered and used by Ziegler during his time as an officer in the Canadian Military during WWII. This includes detailed official battle histories written immediately post conflict by the commanding officer for operational purposes, a draft of Ziegler's unpublished autobiography, and notes taken by Ziegler in his capacity as Deputy Commander of the Hannover Region in Germany following WWII. The fonds is divided into 4 series:

1. Ziegler Biographical
2. Battle and Unit Histories
3. Operations Related Material
4. Miscellaneous