Toronto publisher Wm Collins Sons & Co. Canada Ltd published 459 books between 1942 and 1952 in their paperback series White Circle Pocket Library. From 1952 until 1990, when Wm Collins merged with Harper and Row, other series were published. Here is an example from one of them - Collins Crime. I don't know how many books were published in this series.
Further on are examples of White Circle Pocket Library crime.
Back here I did a post about Kate Aitken and the various books she authored for Wm. Collins Sons & Co. Canada Ltd in the middle of the last century. In this post I'll talk a bit more about one of the books and it's three variants.
It's Fun Raising a Family was a paperback original published in 1955. In addition to a Collins edition there are two branded editions - both for companies that have disappeared.
The edition for Montreal based department store chain Steinberg's (1917-1992) was published half-way through its life. Tamblyn (1904-1978) was a Toronto based drug store chain.
I have just found the last book from early Canadian paperback publisher Export Publishing Enterprises that I needed to complete my collection. As far as I know there are no further books, including reprints.
This is one of two books published in the American series (with the "A") that were unnumbered in the Canadian series. The edition I was missing was the DJ version.