"Lustrous, mercerized, 3-ply combed crochet cotton makes beautiful bedspreads, tablecloths, chair sets"
Hearthside brand Crochet Cotton made it's appearance in 1945 and was heavily promoted in the weekly Sears newspaper advertisements.
Sears, as did most of the thread suppliers, also offered free patterns as promotion. You know, buy the thread and get the pattern for free.
The brand was short lived as, in the early 1950's Sears discontinued selling re-branded thread and began selling the other major brands of the time period.
I have no doubt there are still a number of excellent patterns calling for the Hearthside branded Crochet Cotton. (I don't have much, but hope to come across more). Substitute any brand of suitable size.