Garbage in the Text
-------------------
If `C-l' shows that the text is wrong, try undoing the changes to it
using `C-x u' until it gets back to a state you consider correct. Also
try `C-h l' to find out what command you typed to produce the observed
results.
If a large portion of text appears to be missing at the beginning or
end of the buffer, check for the word `Narrow' in the mode line. If it
appears, the text you don't see is probably still present, but
temporarily off-limits. To make it accessible again, type `C-x n w'.
Note:Narrowing.