The ones with the unattractive but intelligent people explaining theorems in front of blackboards? They were still being shown on television right into the 1980s, usually in the middle of the afternoon when only housewives, career criminals and schoolchildren pretending to be sick could see them. Heaven knows if they were ever watched by students.
Then the dumbing down of television began, or as it's known in Open University lectures, Paddymcguinnessisation or The Vernon Kay Effect, and it seemed that, in the dazzle and cacophony of garish, loud stupidity, there was no room on TV any more for a boffin in front of a blackboard.
But no: it's back. Howard Goodall's Story Of Music (Saturday, BBC Two, 9.30pm) features nothing more than a man who knows his stuff standing in front of a picture. It is the most retro piece of television I have seen for ages, and yet I'm not sure how I feel about it. It's clearly been done this way because of a low budget and, to be fair, the directors do try desperately hard to have moving pictures in every shot, even if it does get a bit literal at times. We do not, for example, need a picture of a railway track when Goodall talks about musical notes that are parallel. I know what parallel means.
The purpose of it all was to go back in time to the beginnings of music. Back, back we went, past the boy bands and the Spice Girls, past Motown and Vera Lynn, past Bach and Beethoven, to the very early days of music, to the music of the hunter-gatherers and Cliff Richard's first single.
It turned out the very first music ever – although it was clearly guesswork – wasn't a man hitting one stone against another (playing rock music?) but men in caves who used singing as a kind of acoustic sat-nav. Certain parts of the caves would produce certain sounds so everyone knew where they were.
From here, Goodall took us through the first days of music from basic singing to early compositions and the first star of singer-songwriting John Dowland, a contemporary of Shakespeare. In between, there were interesting sections on some early instruments (including the lur, a horn from Belgium that looks like a giant, twisted question mark and produces the most hypnotic, melancholic wail) and another on Christian chanting with examples so beautiful even atheists might stop and think: could there be something in religion after all? There was also a chance to hear the first example of muzak, played to customers as they waited in barber shops in Tudor England.
All together, it was reasonably diverting and interesting, so why by the end was I bothered by the feeling there was something missing? Could it have been the essential something that every programme about music needs: passion, love, excitement? Could that explain why this history of music felt a little bloodless, too anodyne; too much like those Open University programmes from the 1970s; too much like a lecture and not enough like a love song?