+=head1 WARNING
+
+The "interpreter-based threads" provided by Perl are not the fast, lightweight
+system for multitasking that one might expect or hope for.  Threads are
+implemented in a way that make them easy to misuse.  Few people know how to
+use them correctly or will be able to provide help.
+
+The use of interpreter-based threads in perl is officially
+L<discouraged|perlpolicy/discouraged>.
+