diff --git a/README.md b/README.md
index bfae8f6..e42a263 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,7 @@
 # book-reference-code
-Reference code of the "Introduction to GIS Programming and Fundamentals with Python and ArcGIS" book
+Reference code of the "[Introduction to GIS Programming and Fundamentals with Python and ArcGIS](https://www.crcpress.com/Introduction-to-GIS-Programming-and-Fundamentals-with-Python-and-ArcGIS/Yang/p/book/9781466510081" book
+The reference code of each folder is named by its associated chapter of the book. Please refer to each chapter for practical instructions.
+
+# Software requirements: 
+*Python 2.7
+*ArcGIS 10.4 and above