mass changes; fix titles; add examples; correct typos; clarifications;
unified style; etc.
diff --git a/Doc/libshelve.tex b/Doc/libshelve.tex
index 0dec230..a232add 100644
--- a/Doc/libshelve.tex
+++ b/Doc/libshelve.tex
@@ -1,7 +1,8 @@
-\section{Built-in module \sectcode{shelve}}
+\section{Standard Module \sectcode{shelve}}
\stmodindex{shelve}
\stmodindex{pickle}
\bimodindex{dbm}
+\bimodindex{gdbm}
A ``shelf'' is a persistent, dictionary-like object. The difference
with ``dbm'' databases is that the values (not the keys!) in a shelf
@@ -48,8 +49,11 @@
or may not be necessary to flush changes to disk.
\item
-The \code{shelve} module does not support {\em concurrent} access to
-shelved objects. Two programs should not try to simultaneously access
-the same shelf.
+The \code{shelve} module does not support {\em concurrent} read/write
+access to shelved objects. (Multiple simultaneous read accesses are
+safe.) When a program has a shelf open for writing, no other program
+should have it open for reading or writing. \UNIX{} file locking can
+be used to solve this, but this differs across \UNIX{} versions and
+requires knowledge about the database implementation used.
\end{itemize}