diff --git a/documentation/environment.rst b/documentation/environment.rst
new file mode 100644
index 0000000..0183366
--- /dev/null
+++ b/documentation/environment.rst
@@ -0,0 +1,118 @@
+Runtime Environment
+===================
+
+The pyDevSup module initializes the interpreter during the registration
+phase of IOC startup with the *pySetupReg* registrar function. ::
+
+  #!../../bin/linux-x86_64/softIocPy
+  # Interpreter not started
+  dbLoadDatabase("../../dbd/softIocPy.dbd",0,0)
+  softIocPy_registerRecordDeviceDriver(pdbbase)
+  # Interpreter started
+
+An *epicsAtExit* cleanup handler is also registered at this time.
+
+Several IOC Shell functions are also registered.
+*py()* executes a line of python code.
+*pyfile()* reads and interprets a python script. ::
+
+  py("import mymod;)
+  py("mymod.makeDev('one')")
+  py("mymod.makeDev('two')")
+  
+  pyfile("myinit.py")
+
+PYTHONPATH
+----------
+
+The interpreter search path is automatically prefixed with the following additional paths:
+
+* ``$(EPICS_BASE)/python<PY_VER>/$(EPICS_ARCH)``
+* ``$(PYDEV_BASE)/python<PY_VER>/$(EPICS_ARCH)``
+* ``$(TOP)/python<PY_VER>/$(EPICS_ARCH)``
+
+The environment variables ``EPICS_BASE``, ``PYDEV_BASE``, ``TOP``, and ``EPICS_ARCH``
+will be used if set.  Compile time defaults are selected for
+``EPICS_BASE``, ``PYDEV_BASE``, ``EPICS_ARCH``.
+If ``TOP`` is not set then the this entry is omitted.
+
+The default for ``PYDEV_BASE`` is the ``$(INSTALL_LOCATION)`` given when the
+pyDevSup module was built.
+
+Build Environment
+=================
+
+When building IOCs or installing files, include ``PYDEVSUP`` in your *configure/RELEASE*
+file. ::
+
+  PYDEVSUP=/dir/where/pyDevSup/is/installed
+  EPICS_BASE=/....
+
+The following should be added to the usual EPICS Makefiles. ::
+
+  TOP=../..
+  include $(TOP)/configure/CONFIG
+  include $(PYDEVSUP)/configure/CONFIG_PY
+  ...
+  include $(TOP)/configure/RULES
+  include $(PYDEVSUP)/configure/RULES_PY
+
+This will add or ammend several make variables.  The ``USR_*FLAGS`` variables
+may be extended with approprate flags for building python modules.  The ``PY_VER``
+variable is defined with the Python version number found in install directories (eg "2.7").
+The ``PY_LD_VER`` variable is defined with the python library version number (eg "3.2mu"),
+which may be the same as ``PY_VER``.
+
+Include pyDevSup in your IOC
+----------------------------
+
+While the *softIocPy* executable built as part of this module
+will be sufficient for many uses, it is also possible to
+include the pyDevSup modules in an IOC along with other drivers.
+This can be done in the usual way. ::
+
+  PROD_IOC = myioc
+  DBD += myioc.dbd
+  ...
+  myioc_DBD += pyDevSup.dbd
+  ...
+  myioc_LIBS += pyDevSup$(PY_LD_VER)
+
+Installing .py files
+--------------------
+
+Additional .py files can be installed as follows. ::
+
+  PY += mymod/__init__.py
+  PY += mymod/file1.py
+
+Building extensions
+-------------------
+
+For convienance, additional Python extensions can be build by the EPICS
+build system.  In this example the extension name is "_myextname" and
+the resulting library is expected to provide the an initialization function
+named "init_myextname". ::
+
+  LOADABLE_LIBRARY_HOST = _myextname
+
+  _myextname_SRCS += somefile.c
+
+In somefile.c ::
+
+  PyMODINIT_FUNC init_myextname(void)
+
+Installing for several Python versions
+------------------------------------
+
+The recipe for building and installing the pyDevSup module
+for several python version side by side is ::
+
+  make PYTHON=python2.6
+  make clean
+  make PYTHON=python2.7
+  make clean
+  make PYTHON=python3
+  make clean
+
+Note that the ``softIocPy`` will by build for the last version only.
diff --git a/documentation/index.rst b/documentation/index.rst
index 52a6001..1fb057e 100644
--- a/documentation/index.rst
+++ b/documentation/index.rst
@@ -11,6 +11,7 @@ Contents:
 .. toctree::
    :maxdepth: 4
 
+   environment
    devsup
    interfaces
 
diff --git a/documentation/interfaces.rst b/documentation/interfaces.rst
index 44186c7..9ff7466 100644
--- a/documentation/interfaces.rst
+++ b/documentation/interfaces.rst
@@ -112,6 +112,13 @@ and the string "some other string".
         def allowScan(self, record):
           return self.a_scan.add(record)
 
+    Which is most cases can be abbriviated to ::
+
+      class MySup(object):
+        def __init__(self):
+          self.a_scan = devsup.db.IOScanListThread()
+          self.allowScan = self.a_scan.add
+
 Example
 -------