Today, the LAC has released a new research guide called "Canada At War: A Guide to Library and Archives Canada's Website Recalling the Canadian War Experience".
For the first time, this guide brings together the complete compendium of resources regarding the First World War available at the LAC ranging from Exhibitions such as Aboriginal Soldiers to Research (Digital Collections/Bibliography) which feature such online databases as Court-Martials of the First Word War, the Soldiers of the First World War, and Canadian Historical Sound Recordings of the First World War Era.
The last item that is mentioned in this itemized list of resources is the "War Diaries of the First World War", and they are very interesting. <www.collectionscanada.gc.ca/veterans/025001-4000-e.html>.
They are not diaries written about the individuals in the war, but diaries of the Canadian Expeditionary Force (CEF), where they were required to keep a daily account of their "Actions in the Field" <www.collectionscanada.gc.ca/archivianet/020152_e.html>.
I checked the establishment of the 1st Canadian Stationary Hospital as it mobilized in Quebec City in September, 1914, and the Cyclist Division with the Canadian Reserve Cyclist Company as they set up their operations.
If you know what unit your ancestor served in during the war, these are very helpful diaries, and offer a bit of reflection into the war. I got the feeling while reading them that they understood what was at hand, and they prepared the best they could for what the four years of the war would bring to them - reward, misery, and death.