diff --git a/book/chapter-01-run-and-talk.md b/book/chapter-01-run-and-talk.md
index 6ba4f9a6..58548f49 100644
--- a/book/chapter-01-run-and-talk.md
+++ b/book/chapter-01-run-and-talk.md
@@ -8,7 +8,10 @@
 
 
 1- gbapp and gblib extensions which are folder extensions for the GeneralBots package type.
-gbapp and gblib are responsible for GeneralBots services in a Back-end development environment
+gbapp and gblib are responsible for GeneralBots services in a Back-end development environment.
+
+2- The .gbui extension is assigned to the GeneralBots front-end development environment. 
+Angular, Riot, React and HTML are responsible for the dynamic functioning of GeneralBots services
 
 ### The Bot Factory