I often find myself debating the content and structure of such courses and I would find it useful to know the basic history.

I don't remember any such offerings during my own undergraduate days in the '70s. I have always supposed these courses appeared as compensation for a decline in high school Euclidean geometry teaching, but I would call my understanding anecdotal.

Some old-timers may have the whole history in their heads, if so thanks. Otherwise it would be useful to me to hear if you had such a course a long time ago (and where, and from who), but please only comment if your date trumps the earliest previously posted date. In any case I feel sure such courses were popular by the 1980s.

Polya's How To Solve It dates to 1945 and roughly addresses these needs, but I have always understood it as a popular book rather than a a text. So I wonder what were the first texts written to support such courses?

Please refrain, of course, from opining about the efficacy or effectiveness of such courses, but feel free to site any published research addressing the same. Thanks.