The box she's standing in front of? That's a theremin!
Everything about this album cover is fun to look at.
photo from http://www.thethereminworld.com/
The theremin is one of the first electronic musical instruments (invented in Russia in 1920) and is the only instrument you play without touching it. Without touching it! It looks like a box with two antennas extending out on opposite sides—one antenna is horizontal and the other is vertical. The notes are controlled by the distance of your hands from the antennas. Freaky? Oh yes it is. Go take a look. I wish I knew how to put a performance on the blog. Some day I will!