Recorded in 1954 and released as "Adventures in Carols", and the rereleased a bit later as a 10" with a third of its songs missing "Xmas Hi-Fivories" (I only just now see that that a portmanteau of "Hi-Fi" with "ivory" and not "favorite" which is much less convoluted, and much easier to pronounce.) Throughout the album is full of piano preparations (that is, sticking pieces of wood, rubber, nuts and bolts, etc in between the piano's strings to alter the sounds) in lieu of the sorts of percussion sounds common in the "exotica" or "space-age" styles. This might be the a reasonable introduction to the sound world of John Cage's pieces for prepared piano. I've no idea where Ferrante and Teicher fit into Cage's orbit, and this is only a decade or so into Cage's experiments with this sound, long before they became the accepted (or at least tolerated) ideas they are today.
Probably more fun than spending Christmas eve with John and Merce