I love secret compartments of all kind. This is great!

my mom designed something similar for her pantry: she has double-sided shelves that swing out to reveal deeper shelves behind. we can store enough food, as our neighbor used to say, to "feed the russian army."

It's surprising how many bookcases do this nowadays.

These are beautiful, and I agree about the appeal of secret spaces. If you have ever been to the Anne Frank House in Amsterdam, you have seen the similar bookcase (smaller) that hid the entrance to the secret area in their house. That's what I thought of as soon as I saw them.

My grandmother had a "secret passageway" through the closet of the front and back bedrooms in her tiny bungalow, and as children we thought it was the most wonderful thing!

This would also be a great way to address an infrequently-used second door to a two-door guest bath, or the opening to a Murphy bed.

"the appeal of secret spaces" like hiding from Nazis? That's a stretch.