diff --git a/docs/Makefile b/docs/Makefile
new file mode 100644
index 0000000..d4bb2cb
--- /dev/null
+++ b/docs/Makefile
@@ -0,0 +1,20 @@
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = .
+BUILDDIR      = _build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
diff --git a/docs/conf.py b/docs/conf.py
new file mode 100644
index 0000000..1fb06da
--- /dev/null
+++ b/docs/conf.py
@@ -0,0 +1,57 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# This file only contains a selection of the most common options. For a full
+# list see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# -- Path setup --------------------------------------------------------------
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#
+import os
+import sys
+sys.path.insert(0, os.path.abspath('..'))
+
+
+# -- Project information -----------------------------------------------------
+
+project = 'pysim'
+copyright = '2021, Sylvain Munaut, Harald Welte, Philipp Maier'
+author = 'Sylvain Munaut, Harald Welte, Philipp Maier'
+
+
+# -- General configuration ---------------------------------------------------
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
+# ones.
+extensions = [
+        "sphinx.ext.autodoc",
+        "sphinx.ext.autosectionlabel",
+        "sphinx.ext.napoleon"
+]
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This pattern also affects html_static_path and html_extra_path.
+exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+
+
+# -- Options for HTML output -------------------------------------------------
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+#
+html_theme = 'alabaster'
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to this directory. They are copied after the builtin static files,
+# so a file named "default.css" will overwrite the builtin "default.css".
+html_static_path = ['_static']
+
+autoclass_content = 'both'
diff --git a/docs/index.rst b/docs/index.rst
new file mode 100644
index 0000000..c647880
--- /dev/null
+++ b/docs/index.rst
@@ -0,0 +1,50 @@
+.. pysim documentation master file
+
+Welcome to Osmocom pySim
+========================
+
+Introduction
+------------
+
+pySim is a python implementation of various software that helps you with
+managing subscriber identity cards for cellular networks, so-called SIM
+cards.
+
+Many Osmocom (Open Source Mobile Communications) projects relate to operating
+private / custom cellular networks, and provisioning SIM cards for said networks
+is in many cases a requirement to operate such networks.
+
+To make use of most of pySim's features, you will need a `programmable` SIM card,
+i.e. a card where you are the owner/operator and have sufficient credentials (such
+as the `ADM PIN`) in order to write to many if not most of the files on the card.
+
+Such cards are, for example, available from sysmocom, a major contributor to pySim.
+See https://www.sysmocom.de/products/lab/sysmousim/ for more details.
+
+pySim supports classic GSM SIM cards as well as ETSI UICC with 3GPP USIM and ISIM
+applications.  It is easily extensible, so support for additional files, card
+applications, etc. can be added easily by any python developer.  We do encourage you
+to submit your contributions to help this collaborative development project.
+
+pySim consists of several parts:
+
+* a python :ref:`library<pySim library>` containing plenty of objects and methods that can be used for
+  writing custom programs interfacing with SIM cards.
+* the [new] :ref:`interactive pySim-shell command line program<pySim-shell>`
+* the [legacy] :ref:`pySim-prog and pySim-read tools<Legacy tools>`
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Contents:
+
+   shell
+   legacy
+   library
+
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
diff --git a/docs/legacy.rst b/docs/legacy.rst
new file mode 100644
index 0000000..492be46
--- /dev/null
+++ b/docs/legacy.rst
@@ -0,0 +1,2 @@
+Legacy tools
+============
diff --git a/docs/library.rst b/docs/library.rst
new file mode 100644
index 0000000..ae027ff
--- /dev/null
+++ b/docs/library.rst
@@ -0,0 +1,92 @@
+pySim library
+=============
+
+pySim filesystem abstraction
+----------------------------
+
+.. automodule:: pySim.filesystem
+   :members:
+
+pySim commands abstraction
+--------------------------
+
+.. automodule:: pySim.commands
+   :members:
+
+pySim Transport
+---------------
+
+The pySim.transport classes implement specific ways how to
+communicate with a SIM card.  A "transport" provides ways
+to transceive APDUs with the card.
+
+The most commonly used transport uses the PC/SC interface to
+utilize a variety of smart card interfaces ("readers").
+
+Transport base class
+~~~~~~~~~~~~~~~~~~~~
+
+.. automodule:: pySim.transport
+   :members:
+
+
+calypso / OsmocomBB transport
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This allows the use of the SIM slot of an an OsmocomBB compatible phone with the TI Calypso chipset,
+using the L1CTL interface to talk to the layer1.bin firmware on the phone.
+
+.. automodule:: pySim.transport.calypso
+   :members:
+
+
+AT-command Modem transport
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This transport uses AT commands of a cellular modem in order to get access to the SIM card inserted
+in such a modem.
+
+.. automodule:: pySim.transport.modem_atcmd
+   :members:
+
+
+PC/SC transport
+~~~~~~~~~~~~~~~
+
+PC/SC is the standard API for accessing smart card interfaces
+on all major operating systems, including the MS Windows Family,
+OS X as well as Linux / Unix OSs.
+
+.. automodule:: pySim.transport.pcsc
+   :members:
+
+
+Serial/UART transport
+~~~~~~~~~~~~~~~~~~~~~
+
+This transport implements interfacing smart cards via
+very simplistic UART readers.  These readers basically
+wire together the Rx+Tx pins of a RS232 UART, provide
+a fixed crystal oscilator for clock, and operate the UART
+at 9600 bps.  These readers are sometimes called `Phoenix`.
+
+.. automodule:: pySim.transport.serial
+   :members:
+
+pySim utility functions
+-----------------------
+
+.. automodule:: pySim.utils
+   :members:
+
+pySim exceptions
+----------------
+
+.. automodule:: pySim.exceptions
+   :members:
+
+pySim card_handler
+------------------
+
+.. automodule:: pySim.card_handler
+   :members:
diff --git a/docs/make.bat b/docs/make.bat
new file mode 100644
index 0000000..2119f51
--- /dev/null
+++ b/docs/make.bat
@@ -0,0 +1,35 @@
+@ECHO OFF
+
+pushd %~dp0
+
+REM Command file for Sphinx documentation
+
+if "%SPHINXBUILD%" == "" (
+	set SPHINXBUILD=sphinx-build
+)
+set SOURCEDIR=.
+set BUILDDIR=_build
+
+if "%1" == "" goto help
+
+%SPHINXBUILD% >NUL 2>NUL
+if errorlevel 9009 (
+	echo.
+	echo.The 'sphinx-build' command was not found. Make sure you have Sphinx
+	echo.installed, then set the SPHINXBUILD environment variable to point
+	echo.to the full path of the 'sphinx-build' executable. Alternatively you
+	echo.may add the Sphinx directory to PATH.
+	echo.
+	echo.If you don't have Sphinx installed, grab it from
+	echo.http://sphinx-doc.org/
+	exit /b 1
+)
+
+%SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+goto end
+
+:help
+%SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+
+:end
+popd
diff --git a/docs/shell.rst b/docs/shell.rst
new file mode 100644
index 0000000..f9a2c82
--- /dev/null
+++ b/docs/shell.rst
@@ -0,0 +1,2 @@
+pySim-shell
+===========