diff --git a/binary_search_tree/tree.py b/binary_search_tree/tree.py
index cdd5abc..b558a8c 100644
--- a/binary_search_tree/tree.py
+++ b/binary_search_tree/tree.py
@@ -1,10 +1,10 @@
 class TreeNode:
-    def __init__(self, key, val = None):
-        if val == None:
-            val = key
+    def __init__(self, key, value = None):
+        if value == None:
+            value = key
 
         self.key = key
-        self.value = val
+        self.value = value
         self.left = None
         self.right = None
         
@@ -14,36 +14,113 @@ class Tree:
     def __init__(self):
         self.root = None
 
-    # Time Complexity: 
-    # Space Complexity: 
+
+    def add_helper(self, current_node, key, value):
+        if current_node == None:
+            return TreeNode(key, value)     
+        if key <= current_node.key:
+            current_node.left = self.add_helper(current_node.left, key, value)
+        else:
+            current_node.right = self.add_helper(current_node.right, key, value)
+        return current_node
+
+
+    # Time Complexity: O(log n) - balanced
+    # Space Complexity: O(log n)
     def add(self, key, value = None):
-        pass
+        if self.root == None:
+            self.root = TreeNode(key, value)
+        else:
+            self.add_helper(self.root, key, value)
+
+
+    def find_helper(self, current, key):
+        if current == None:
+            return None
+        elif current.key == key:
+            return current.value
+        elif key < current.key:
+            return self.find_helper(current.left, key)
+        else:
+            return self.find_helper(current.right, key)
+
 
-    # Time Complexity: 
-    # Space Complexity: 
+    # Time Complexity: O(n)
+    # Space Complexity: O(n)
     def find(self, key):
-        pass
+        return self.find_helper(self.root, key)
+
+
+    def inorder_helper(self, current, traversal_list):
+        if current == None:
+            return None
+        self.inorder_helper(current.left, traversal_list)
+        traversal_list.append({
+                "key": current.key,
+                "value": current.value
+            })
+        self.inorder_helper(current.right, traversal_list)
+
 
-    # Time Complexity: 
-    # Space Complexity: 
+    # Time Complexity: O(n)
+    # Space Complexity: O(n)
     def inorder(self):
-        pass
+        traversal_list = []
+        self.inorder_helper(self.root, traversal_list)
+        return traversal_list
+
+
+    def preorder_helper(self, current, traversal_list):
+        if current != None:
+            traversal_list.append({
+                "key": current.key,
+                "value": current.value
+            })
+            self.preorder_helper(current.left, traversal_list)
+            self.preorder_helper(current.right, traversal_list)
 
-    # Time Complexity: 
-    # Space Complexity:     
+
+    # Time Complexity: O(n)
+    # Space Complexity: O(n)    
     def preorder(self):
-        pass
+        traversal_list = []
+        self.preorder_helper(self.root, traversal_list)
+        return traversal_list
+
+
+    def postorder_helper(self, current, traversal_list):
+        if current == None:
+            return None
+        self.postorder_helper(current.left, traversal_list)   
+        self.postorder_helper(current.right, traversal_list)   
+        traversal_list.append({
+            "key": current.key,
+            "value": current.value
+        })
 
-    # Time Complexity: 
-    # Space Complexity:     
+
+    # Time Complexity: O(n)
+    # Space Complexity: O(n)    
     def postorder(self):
-        pass
+        traversal_list = []
+        self.postorder_helper(self.root, traversal_list)
+        return traversal_list
+
+
+    def height_helper(self, current):
+        if current == None:
+            return 0
+        else:
+            left = self.height_helper(current.left)
+            right = self.height_helper(current.right)
+        return max(left,right) + 1
 
-    # Time Complexity: 
-    # Space Complexity:     
-    def height(self):
-        pass
 
+    # Time Complexity: O(n)
+    # Space Complexity: O(n)
+    def height(self):
+        current = self.root
+        return self.height_helper(current)
 
 #   # Optional Method
 #   # Time Complexity: 
@@ -52,8 +129,6 @@ def bfs(self):
         pass
 
         
-
-
 #   # Useful for printing
     def to_s(self):
         return f"{self.inorder()}"