There's a great 80-minute documentary about Theremin – I heartily recommend it. The highlight is a very trippy interview with Brian Wilson of the Beach Boys -- the interview really has to be seen to be believed:

https://www.youtube.com/watch?v=j_0WmqnC6eA

Looks like the documentary is no longer on Netflix, but it is on Amazon Prime streaming. Rotten Tomatoes for the movie:

https://www.rottentomatoes.com/m/theremin_an_electronic_odys...