diff --git a/doc/guide/admin/overlays.sdf b/doc/guide/admin/overlays.sdf
index 175931e908..d49586c636 100644
--- a/doc/guide/admin/overlays.sdf
+++ b/doc/guide/admin/overlays.sdf
@@ -855,6 +855,14 @@ H2: Overlay Stacking
 
 H3: Overview
 
+Overlays can be stacked, which means that more than one overlay
+can be instantiated for each database, or for the frontend.
+As a consequence, each overlay's function is called, if defined,
+when overlay execution is invoked.
+Multiple overlays are executed in reverse order (it's a stack, all in all)
+with respect to their definition in slapd.conf (5), or with respect
+to their ordering in the config database, as documented in slapd-config (5).
+
 
 H3: Example Scenarios