Sylvia Lovegren knew she’d found something unusual while going through a box of used books, but she had no idea how rare it would turn out to be. A volunteer with the Friends of the Kelly Library at St. Michael’s College, Ms. Lovegren helps sort the 70,000 to 100,000 books donated to its fundraising sale every year.

She made the discovery while examining a collection of books relating to the Second World War in case some should be priced above the normal top price of $5. “I opened one up and I thought ‘what is this little piece of paper thing in here?

“It was just tucked inside the pages, and it looked like a comic book, and it had a very graphic design on it.”

Titled Jewish War Heroes and dated 1944, “it was in very good condition, so I thought it was something that had been issued much later,” she says. “But when I looked it up, I found that it had actually been issued during the war — and it was rather scarce. You can get a digital copy of it, but actual copies of it are very hard to come by.”

As Ms. Lovegren discovered, the comic book was the first of three issues published by the Canadian Jewish Congress to highlight the courage and dedication of Jewish soldiers at a time when some Canadians were claiming that Jews weren’t doing enough for the war effort.

In her 2012 book Nazi Germany, Canadian Responses : Confronting Antisemitism in the Shadow of War, Ruth Klein reveals that the comic books were among numerous strategies of the CJC’s War Efforts Committee “to counteract the myth about Jewish ‘shirking.’”

Ms. Klein writes that the committee opened recruiting centres in Toronto and Montreal and kept careful track of enlistment figures, which were then circulated to media. They also held rallies across the country, circulated a monthly journal called Jews in Uniform and provided practical support to soldiers in the form of “comfort boxes” sent overseas and servicemen’s centres in Canada.

The first issue of Canadian War Heroes documents the career of Hamilton native Bert “Yank” Levy, who wrote a well-known book on guerilla warfare techniques, and even made the cover of Life magazine in 1942, as well as two recipients of the Distinguished Flying Cross (Brigadier Frederick Hermann Kisch and Alfred Brenner); General Morrice Abraham Cohen, an aide-de-camp to Sun Yat-sen, and Soviet submarine captain Israel Fisanovitch.

Ms. Lovegren has only located a few other copies of the comic book. “There are two library-bound copies in Toronto; this one was still pristine, without anybody fiddling with the binding,” Ms. Lovegren says. “Other than that, there is a copy in the Holocaust Memorial Museum in Washington DC and one in the National Library of Israel. It’s a very important little artifact. It was very thrilling to find it and to realize what it was.”

It would be tricky to fix a price on such a find, says Peter Birkemoe, owner of Toronto comic book shop The Beguiling. “With any Canadian wartime comics, it is more difficult than most comics, because there aren’t published records of sales figures like there are for things that trade hands more often; particularly for older comic books where the number of existing copies is fewer than 100.”

At auction, he says, if there was competition between bidders interested in Canadian or Jewish items, or collectors attracted by its rarity, “your low end would be in the $1,000 range; your high end would be close to five figures.”

This isn’t the first treasure that’s turned up among the donations, says Caroline Di Giovanni, President of the Friends of the Kelly Library. Past highlights include valuable nature prints, books relating to Marshall McLuhan and unique music memorabilia from Father Owen Lee, a regular panelist on the Texaco Opera Quiz. This year, notable donations include music scores, books on heraldry and Gaelic language and “a complete collection of 19th-century Trollope books,” says Ms. Di Giovanni.

Saturday is the final day of this year’s sale. Jewish War Heroes will be on display but not for sale; the library will likely keep it.