diff --git a/app/args.py b/app/args.py
index 120dfb1..400b448 100644
--- a/app/args.py
+++ b/app/args.py
@@ -1,5 +1,7 @@
 #!/usr/local/env python3
 
+"""MODULE: Provides CLI arguments to the application."""
+
 import argparse
 
 from app.query_normalisation import get_public_ip
diff --git a/app/ip_info.py b/app/ip_info.py
index 9a349ce..ade9dde 100644
--- a/app/ip_info.py
+++ b/app/ip_info.py
@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 
+"""MODULE: Provides functions to call various APIs to retrieve IP/prefix information."""
+
 import ipaddress
 import requests
 
diff --git a/app/main.py b/app/main.py
index 1acf2de..898afb8 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1,5 +1,7 @@
 #!/usr/local/bin/python3
 
+"""MODULE: Main application module."""
+
 import sys
 
 from app.args import parse_args
diff --git a/app/print_table.py b/app/print_table.py
index a5813b6..fd9f118 100644
--- a/app/print_table.py
+++ b/app/print_table.py
@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 
+"""MODULE: Provides functions for preparing, then printing, retrieved data."""
+
 from tabulate import tabulate
 
 
diff --git a/app/query_normalisation.py b/app/query_normalisation.py
index fe0cb31..5bf32fd 100644
--- a/app/query_normalisation.py
+++ b/app/query_normalisation.py
@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 
+"""MODULE: Provides functions that ensure an IP address is available to query the APIs for."""
+
 import socket
 import ipaddress
 import requests
diff --git a/tests/test_ip_info.py b/tests/test_ip_info.py
index 5b5d79b..ea84846 100644
--- a/tests/test_ip_info.py
+++ b/tests/test_ip_info.py
@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 
+"""MODULE: Provides test cases for app/ip_info.py."""
+
 from app.ip_info import (  # pragma: no cover
     get_ip_information,
     get_autonomous_system_number,
diff --git a/tests/test_main.py b/tests/test_main.py
index 147f528..ebbdd22 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 
+"""MODULE: Provides test cases for app/main.py."""
+
 # from app.ip import is_ip_address
 
 
diff --git a/tests/test_query_normalisation.py b/tests/test_query_normalisation.py
index 4a58abd..6fdd6a6 100644
--- a/tests/test_query_normalisation.py
+++ b/tests/test_query_normalisation.py
@@ -1,5 +1,7 @@
 #!/usr/bin/env python3
 
+"""MODULE: Provides test cases for app/query_normalisation.py."""
+
 from app.query_normalisation import (  # pragma: no cover
     is_ip_address,
     resolve_domain_name,