other buffers, and never happen to switch back, you have exited. Just
make sure to save the Rmail file eventually (like any other file you
have changed). @kbd{C-x s} is a good enough way to do this
-(@pxref{Saving}). The Rmail command @kbd{b}, @code{rmail-bury},
+(@pxref{Save Commands}). The Rmail command @kbd{b}, @code{rmail-bury},
buries the Rmail buffer and its summary buffer without expunging and
saving the Rmail file.