diff --git a/Chapter3-Modules and Program Organization/mix-ins.rb b/Chapter3-Modules and Program Organization/mix-ins.rb
new file mode 100644
index 0000000..530d838
--- /dev/null
+++ b/Chapter3-Modules and Program Organization/mix-ins.rb	
@@ -0,0 +1,19 @@
+#Modules dont have instances, instead modules get mixed-in 
+#to classes, using the include method
+
+#The result of mixing in a module is that instances of the class have 
+#acces to the instance methods defined in the module.
+
+
+module MyFirstModule
+  def say_hello
+    puts "Hello"
+  end
+end
+
+class ModuleTester
+  include MyFirstModule
+end
+
+mt = ModuleTester.new
+mt.say_hello
diff --git "a/Chapter3-Modules and Program Organization/stack_program/\\" "b/Chapter3-Modules and Program Organization/stack_program/\\"
new file mode 100644
index 0000000..9cee028
--- /dev/null
+++ "b/Chapter3-Modules and Program Organization/stack_program/\\"	
@@ -0,0 +1,54 @@
+import sys
+import os
+import pdb
+
+def man():
+	print ("=========  help page  ==========")
+	print ("python3 todo.py [OPTION]...")
+	print ("\t -a \"TASK\" \n\t\t Add task")
+	print ("\t -v \n\t\t List all task")
+	print ("\t -s \n\t\t Seek task")
+	print ("\n=========  To DO App  ==========")
+	sys.exit(1)
+############ Append Function #############
+def add():
+	if len(sys.argv) != 3:
+		print ("Add task")
+		print ("\t e.g -  python3 todo.py -a \"TASK\"")
+	else:
+		task = sys.argv[2]
+		if os.path.isfile("./task.txt"):
+			f=open("./task.txt","a")
+			f.write(task + "\n")
+			f.close()
+			print ("Task added")
+		else:
+			f=open("./task.txt","w")
+			f.write(task + "\n")
+			f.close()
+			print ("Task added")
+############ Display Function #############
+def display():
+	if os.path.isfile("task.txt"):
+		f=open("task.txt","r")
+		print (f.read())
+		f.close()
+	else:
+		print ("File not exist \t Please add task first")
+
+###### Main Function #########
+def main():
+	if len(sys.argv) <= 1:
+		man()
+	elif len(sys.argv) >= 1:
+		if (sys.argv[1]=="-a"):
+			add()
+		elif (sys.argv[1]=="-v"):
+			display()
+                elif (sys.argv[1]=="-d"):
+                        pass
+                elif (sys.argv[1]=="-u"):
+                        pass
+
+main()
+
diff --git a/Chapter3-Modules and Program Organization/stack_program/stack.rb b/Chapter3-Modules and Program Organization/stack_program/stack.rb
new file mode 100644
index 0000000..34bcce2
--- /dev/null
+++ b/Chapter3-Modules and Program Organization/stack_program/stack.rb	
@@ -0,0 +1,21 @@
+require_relative "stacklike"
+
+class Stack
+  include Stacklike
+end
+
+s = Stack.new
+s.add_to_stack("item one")
+s.add_to_stack("item two")
+s.add_to_stack("item three")
+
+puts "\nObjects currently on stack"
+puts s.stack
+
+taken = s.take_from_stack
+puts "\nRemoved this object: "
+puts taken
+
+puts"\nNow on stack"
+puts s.stack
+
diff --git a/Chapter3-Modules and Program Organization/stack_program/stacklike.rb b/Chapter3-Modules and Program Organization/stack_program/stacklike.rb
new file mode 100644
index 0000000..8f0c04f
--- /dev/null
+++ b/Chapter3-Modules and Program Organization/stack_program/stacklike.rb	
@@ -0,0 +1,13 @@
+module Stacklike
+  def stack
+    @stack ||= []
+  end
+
+  def add_to_stack(obj)
+    stack.push(obj)
+  end
+
+  def take_from_stack
+    stack.pop
+  end
+end
diff --git a/Chapter3-Modules and Program Organization/super.rb b/Chapter3-Modules and Program Organization/super.rb
new file mode 100644
index 0000000..80b76cc
--- /dev/null
+++ b/Chapter3-Modules and Program Organization/super.rb	
@@ -0,0 +1,18 @@
+module Maintain
+  def report
+    puts "'report' method in module Maintain"
+  end
+end
+
+class Contains
+  include Maintain
+  def report
+    puts "'report' method in class Contains"
+    puts "About to trigger the next higher-up report method..." 
+    super
+    puts "Back from the 'super' call"
+  end
+end
+
+c = Contains.new
+c.report