I'm accustomed to tolerating puff pieces about the theremin - a podcast where the creator plays a few minutes of The Day The Earth Stood Still, reads the Wikipedia page, and giggles.
This is not one of those. This is an almost impossibly well researched, entertaining and informative couple of hours. If someone wanted to learn almost everything about the history of the instrument, this would be the piece I'd give them. The presenter mentions all of the well-known performers, gives just a little technical detail, emphasizes what a brutally difficult instrument it is to master, and alternates very gracefully between talk and music - with, as the title of the series suggests, an emphasis on movie music.
Two thumbs up!