Reader Graham asked a great question that I don't know the answer to, offhand (he also asked a Hockey question that I answered over at Sports Legends Revealed).
The question is this - When did Batman first disappear from a room (or from the roof top talking to Gordon)? Was it a long time ago, or was it a recent (i.e. 80s/90s) invention?
Everyone think of the earliest that they have seen it happen!
Thanks to Graham for the question!