Fill-in the introductory paragraph for the library tour.
diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex
index 86ba0c3..79ae365 100644
--- a/Doc/tut/tut.tex
+++ b/Doc/tut/tut.tex
@@ -4765,6 +4765,9 @@
 
 \chapter{Brief Tour of the Standard Library -- Part II\label{briefTourTwo}}
 
+This second tour covers more advanced modules that support professional
+programming needs.  These modules rarely occur in small scripts.
+
 
 \section{Output Formatting\label{output-formatting}}