diff --git a/doc/images/mainClassDiagram.png b/doc/images/mainClassDiagram.png
index 344408fea..ef43f7ce1 100644
Binary files a/doc/images/mainClassDiagram.png and b/doc/images/mainClassDiagram.png differ
diff --git a/src/seedu/addressbook/data/AddressBook.java b/src/seedu/addressbook/data/AddressBook.java
index a99a92f9f..efbc6f951 100644
--- a/src/seedu/addressbook/data/AddressBook.java
+++ b/src/seedu/addressbook/data/AddressBook.java
@@ -1,5 +1,6 @@
 package seedu.addressbook.data;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
@@ -11,6 +12,7 @@
 import seedu.addressbook.data.person.UniquePersonList.DuplicatePersonException;
 import seedu.addressbook.data.person.UniquePersonList.PersonNotFoundException;
 import seedu.addressbook.data.tag.Tag;
+import seedu.addressbook.data.tag.Tagging;
 import seedu.addressbook.data.tag.UniqueTagList;
 
 /**
@@ -24,7 +26,7 @@ public class AddressBook {
 
     private final UniquePersonList allPersons;
     private final UniqueTagList allTags; // can contain tags not attached to any person
-
+    private static ArrayList<Tagging> taggingList = new ArrayList<Tagging>();
     /**
      * Creates an empty address book.
      */
@@ -121,6 +123,13 @@ public UniqueTagList getAllTags() {
         return new UniqueTagList(allTags);
     }
 
+    /**
+     *Return a list of tagging which store all sessions where a tag is added or removed from a specific person
+     */
+    public static ArrayList<Tagging> getTaggingList() {
+        return taggingList;
+    }
+
     @Override
     public boolean equals(Object other) {
         return other == this // short circuit if same object
diff --git a/src/seedu/addressbook/data/tag/Tagging.java b/src/seedu/addressbook/data/tag/Tagging.java
new file mode 100644
index 000000000..3f410a533
--- /dev/null
+++ b/src/seedu/addressbook/data/tag/Tagging.java
@@ -0,0 +1,31 @@
+package seedu.addressbook.data.tag;
+
+import seedu.addressbook.data.person.Person;
+
+/**
+ * Store adding or deleting a tag for a specific person that happened during that session.
+ */
+public class Tagging {
+
+    private String personName;
+    private String tagName;
+    private String methodType;
+
+    public Tagging(String personName, String tagName, String methodType) {
+        this.personName = personName;
+        this.tagName = tagName;
+        this.methodType = methodType;
+    }
+
+    public String getPersonName() {
+        return this.personName;
+    }
+
+    public String getTagName() {
+        return this.tagName;
+    }
+
+    public String getMethodType() {
+        return methodType;
+    }
+}
\ No newline at end of file