Your library likely won't inform you there's a digitized copy

At Saturday's Ottawa Branch OGS meeting speaker Carol Reid, Collections Specialist with the Canadian War Museum, used a soldier from the Denison family of Toronto to illustrate how the contents of the George Metcalf Archival Collection and the Hartland Molson Library of the Museum’s Military History Research Centre could be of help to the genealogist.
During the question period I asked about digitized material and Carol responded they try to provide Google Books and/or Internet Archive links from their catalogue.
One of the MHRC Denison holdings is Historical record of the Governor-General's Body Guard and its standing orders / by Frederick C. Denison. It was published in 1876 so is well out of copyright. That should be a signal a digitized version is available for free. That's the case; see https://archive.org/details/historicalrecor01denigoog.
Linking to newly digitized books is a librarian's treadmill. Lots of work, little return.
If you search a library catalogue are you likely to find out whether there's a digitized copy? I checked out a few. Physical copies of Historical record of the Governor-General's Body Guard and its standing orders are held by Carleton University, the University of Ottawa, Library and Archives Canada, the Canadian War Museum MHRC, and the Toronto Public Library. Only two had links to digitized versions, the TPL has what appears to be a local pdf copy online, while the U of Ottawa had a link through its WorldCat catalogue. A few Canadian public libraries had physical copies but no link to a digitized version, a facility not offered by their Bibliocommons hosted catalogue.
The bottom line is not to expect to find information on digitized copies of older publications on most institutional library catalogues. The best bet is to do a Google search for the title which will find Internet Archive and Google Books digitized editions, or a WorldCat search.