It's basically Joe Rogan for smart and sane people. None of the grifters, all of the scientists + academics. Been going on forever, covering a huge range of subjects.
Joe Rogan? Was interested, now no longer. Using Joe Rogan to describe a podcast cheapens your pitch. Unless your saying the podcast is trying to have incredibly broad appeal without much consideration to intelligent thought or the impacts of what they are putting out to the world except in order to increase their own viewership numbers.
Joe Rogan occasionally has some super interesting podcasts where he invites an academic/expert or two out to talk about their specialisation. He listens, occasionally asking a question.
That's how I first encountered him - he was interviewing John Carmack. The later episodes were disappointing, but I spent a year keeping an eye on the guest list. There were maybe 4-5 really good interviews in that year.
In Our Time is like those good episodes but with an extremely high signal-to-noise ratio and generally better.
And note that when you click to an episode to see who the guests are (usually three professors or other experts on the given topic) there's also a reading list.
I guess it's similar to Joe Rogan's show in that it's a recording of people speaking.