diff --git a/HOWTO.md b/HOWTO.md
index ad7e708..91ffcb4 100644
--- a/HOWTO.md
+++ b/HOWTO.md
@@ -6,6 +6,8 @@ This document explains the installation requirements, installation procedure and
 
 See also the general information on coleto in the [README](https://github.com/dh-trier/coleto/blob/main/README.md). 
 
+For a detailed documentation of all functions, please open the [API reference](/docs/index.html) in your browser. 
+
 ## Requirements
 
 Python 3. This package has been tested with Python 3.7. It should also work with Python 3.6+
diff --git a/coleto/meta_documentation.py b/coleto/meta_documentation.py
index a0fafb8..157bc1e 100644
--- a/coleto/meta_documentation.py
+++ b/coleto/meta_documentation.py
@@ -3,7 +3,9 @@
 # Author: Christof Schöch, 2016-2019.
 
 """
-Script to save settings and parameters to disk for documentation.
+Script to save settings and parameters to disk for documentation. 
+Each time coleto is run, a timestamped file is created with this information.
+The purpose is to document, for any results, the parameters used. 
 
 Part of coleto, see: https://github.com/dh-trier/coleto.
 """
diff --git a/coleto/meta_parameters.py b/coleto/meta_parameters.py
index 62832d9..8b6403d 100644
--- a/coleto/meta_parameters.py
+++ b/coleto/meta_parameters.py
@@ -3,7 +3,11 @@
 # Author: Christof Schöch, 2016-2021.
 
 
-"""Script to define and generate parameters, such as paths and filenames.
+"""
+Script to collect and generate parameters, such as paths and filenames.
+The user-defined parameters from the config.yaml file are included here. 
+Additional parameters are generated based on them. 
+All parameters are packaged-up in the 'params' variable. 
 The parameters are then used by the various coleto modules.
 
 Part of coleto, see: https://github.com/dh-trier/coleto.
diff --git a/coleto/run_coleto.py b/coleto/run_coleto.py
index fa9d084..b4ae2e9 100644
--- a/coleto/run_coleto.py
+++ b/coleto/run_coleto.py
@@ -4,8 +4,10 @@
 
 
 """
-Script that runs the coleto text collation pipeline.
-Please see the readme.md file and the documentation.
+This is the main script that controls the coleto text collation pipeline.
+
+For more information, please see the README.md and HOTWO.md files.
+An API reference can be found in the docs folder.
 """
 
 
diff --git a/coleto/stats_distribution.py b/coleto/stats_distribution.py
index 2140e41..99498df 100644
--- a/coleto/stats_distribution.py
+++ b/coleto/stats_distribution.py
@@ -4,7 +4,8 @@
 
 """
 Script to create some statistics from the diff analysis data.
-These statistics focus on the edit types. 
+These statistics focus on the frequency of the various edit types. 
+Based on these statistics, several barcharts can be generated.
 
 Part of coleto, see: https://github.com/dh-trier/coleto.
 """
diff --git a/coleto/text_wdiff.py b/coleto/text_wdiff.py
index 350b5de..a618c05 100644
--- a/coleto/text_wdiff.py
+++ b/coleto/text_wdiff.py
@@ -5,6 +5,10 @@
 """
 Uses subprocess to call wdiff from the command line.
 You need to have wdiff installed.
+Based on the input texts split into sentences,
+wdiff first aligns the text, identifying insertions and deletions. 
+It then identifies each location of difference between two aligned sentences.
+A sanity check is included to make sure wdiff has run correctly.
 """
 
 
diff --git a/coleto/viz_distribution.py b/coleto/viz_distribution.py
index ca740fb..858eb93 100644
--- a/coleto/viz_distribution.py
+++ b/coleto/viz_distribution.py
@@ -4,6 +4,8 @@
 
 """
 Script to visualize some basic collation statistics.
+The key information visualized is frequency of edit types.
+Uses the pygal library to create several barcharts in SVG.
 
 Part of coleto, see: https://github.com/dh-trier/coleto.
 """
diff --git a/coleto/viz_progression.py b/coleto/viz_progression.py
index c06a7e3..196c804 100644
--- a/coleto/viz_progression.py
+++ b/coleto/viz_progression.py
@@ -5,6 +5,10 @@
 """
 Visualize edit intensity over textual progression.
 Relies on cumulated Levenshtein distances per sentence.
+Uses the pygal library to create a barchart. 
+Uses scipy for some smoothing. 
+Input: The distribution statistics. 
+Ouptut: Saves an SVG file to disk. 
 
 Part of coleto, see: https://github.com/dh-trier/coleto.
 """