Where else would the arrival of some vintage encyclopedias be an occasion for such glee?
I've been browsing the pages since I first
mentioned them on Thursday and the more I read the more I love them. I had the idea of using a set like this as a general information source for players a while ago, but didn't get around to actually doing it until recently. This particular collection, the 1922 edition of "Winston's Cumulative Loose-Leaf Encyclopedia", cost less than $40 with shipping via media mail on Ebay, and that seems to be a typical ending price for sets from this era.
Here's a look at the entire ten volume set. The covers have a good amount of natural wear and the spines and tops of the books are dingy with close to 90 years of dust. I'm going to clean them up over the weekend, but I want to be careful not to get them damp or use any solvents that will cause damage. The books are resting on the vintage travel trunk where I store all my props. It's obviously in need of a dusting. Heh.

The inside cover of the first volume, showing the Chicago screws that hold everything together. There's some light corrosion staining from the metal, but I most of that will wipe off. Mail order books were a huge industry in the 20's and 30's and subscription based sets like this were pretty common. The last volume still has a complete sheet of the coupons you sent in to get updated pages from the publisher.

The interiors of the books are absolutely pristine. Given the lack of yellowing I suspect these were printed on quality paper and stored in a benign home environment since they were published. This map of Antarctica demonstrates one of the coolest things about vintage reference works- seeing just how much was unknown. Most of the continent was still a mystery, so there are only some tentative boundaries for the ice floes. The flurry of expeditions in the 20's and 30's would eventually fill in the details that are absent here.

The article on Egypt, showing off some of the graphics the encyclopedias are filled with. Once I match the paper stock I'll be able to modify the existing articles and add details appropriate to particular scenarios. I'm really excited about the possibilities.

Just imagine having players uncover some clues about trouble at a dig in Egypt and then letting them browse through the encyclopedia for more background information. They discover Ephraim Stieglitz is the archeologist in charge...and there's an article describing his education, career, and the unfortunate mishaps that have happened at previous sites he was supervising. They can see exactly where they'll be traveling, since you customized the map of Egypt ahead of time to add the town near the excavation. And the reclusive patron funding Stieglitz's dig? Why, he just happens to have an article too!
Admittedly, this approach isn't for everyone because of the prep work involved. Even without that additional effort I think "Call of Cthulhu" players will find vintage encyclopedias a worthwhile investment, if only for the amount of information you'll have at your fingertips about life in the classic era.