diff --git a/determinate2x2.py b/determinate2x2.py
index a5fa58d..db34cfe 100644
--- a/determinate2x2.py
+++ b/determinate2x2.py
@@ -1,4 +1,21 @@
 from typing import List
+"""
+Calculates the determinant of a 2x2 matrix.
+Args:
+    llist (List[List[int]]): A 2x2 matrix represented as a list of two lists, each containing two integers.
+Returns:
+    int: The determinant of the 2x2 matrix.
+Raises:
+    AssertionError: If the input is not a 2x2 matrix.
+Example:
+    >>> det2x2([[1, 2], [3, 4]])
+    -2
+    
+NOTE: You call the module with determinate2x2.det2x2(M) where M is the 2x2 matrix.  If M is not a 2x2 matrix,
+you will receive an AssertionError: "Matrix is not 2x2"
+    
+"""
+
 
 def det2x2(llist: List[List[int]])->int:
     assert len(llist) == 2 and len(llist[0]) == 2, "Matrix is not 2x2"
diff --git a/determinate3x3.py b/determinate3x3.py
index 87d0bda..cfc202b 100644
--- a/determinate3x3.py
+++ b/determinate3x3.py
@@ -1,4 +1,17 @@
 from typing import List
+"""
+Module for calculating the determinant of a 3x3 matrix.
+Functions:
+    neg_odd_vals(lst: List[int]) -> List[int]:
+        Returns a new list where every value at an odd index is negated.
+    det3x3(M: List[List[int]]) -> int:
+        Calculates and returns the determinant of a 3x3 matrix M using Laplace expansion along the first row.
+        Requires an external module 'determinate2x2' with a function 'det2x2' for 2x2 determinants.
+        
+NOTE: You call determinate3x3.det3x3(M) to find the determinate of matrix M.  If M is not a 3x3 matrix, you 
+will receive an AssertionError: "Matrix is not 3x3"
+        
+"""
 import determinate2x2
 import copy