diff --git a/electrumx_rpc.py b/electrumx_rpc.py
index 68fc74c..2ce4dee 100755
--- a/electrumx_rpc.py
+++ b/electrumx_rpc.py
@@ -1,8 +1,15 @@
 #!/usr/bin/env python3
-
-# See the file "LICENSE" for information about the copyright
+#
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Script to send RPC commands to a running ElectrumX server.'''
+
+
 import argparse
 import asyncio
 import json
diff --git a/lib/coins.py b/lib/coins.py
index 30a0b12..6537e74 100644
--- a/lib/coins.py
+++ b/lib/coins.py
@@ -1,6 +1,15 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Module providing coin abstraction.
+
+Anything coin-specific should go in this file and be subclassed where
+necessary for appropriate handling.
+'''
 
 from decimal import Decimal
 import inspect
@@ -12,7 +21,7 @@ from lib.tx import Deserializer
 
 
 class CoinError(Exception):
-    pass
+    '''Exception raised for coin-related errors.'''
 
 
 class Coin(object):
@@ -24,17 +33,20 @@ class Coin(object):
     VALUE_PER_COIN = 100000000
 
     @staticmethod
-    def coins():
+    def coin_classes():
+        '''Return a list of coin classes in declaration order.'''
         is_coin = lambda obj: (inspect.isclass(obj)
                                and issubclass(obj, Coin)
                                and obj != Coin)
         pairs = inspect.getmembers(sys.modules[__name__], is_coin)
-        # Returned in the order they appear in this file
         return [pair[1] for pair in pairs]
 
     @classmethod
     def lookup_coin_class(cls, name, net):
-        for coin in cls.coins():
+        '''Return a coin class given name and network.
+
+        Raise an exception if unrecognised.'''
+        for coin in cls.coin_classes():
             if (coin.NAME.lower() == name.lower()
                     and coin.NET.lower() == net.lower()):
                 return coin
@@ -43,13 +55,14 @@ class Coin(object):
 
     @staticmethod
     def lookup_xverbytes(verbytes):
+        '''Return a (is_xpub, coin_class) pair given xpub/xprv verbytes.'''
         # Order means BTC testnet will override NMC testnet
-        for coin in Coin.coins():
+        for coin in Coin.coin_classes():
             if verbytes == coin.XPUB_VERBYTES:
                 return True, coin
             if verbytes == coin.XPRV_VERBYTES:
                 return False, coin
-        raise CoinError("version bytes unrecognised")
+        raise CoinError('version bytes unrecognised')
 
     @classmethod
     def address_to_hash168(cls, addr):
@@ -129,7 +142,7 @@ class Coin(object):
 
     @classmethod
     def prvkey_WIF(privkey_bytes, compressed):
-        "Return the private key encoded in Wallet Import Format."
+        '''Return the private key encoded in Wallet Import Format.'''
         payload = bytearray([cls.WIF_BYTE]) + privkey_bytes
         if compressed:
             payload.append(0x01)
@@ -137,18 +150,22 @@ class Coin(object):
 
     @classmethod
     def header_hashes(cls, header):
-        '''Given a header return the previous block hash and the current block
-        hash.'''
+        '''Given a header return the previous and current block hashes.'''
         return header[4:36], double_sha256(header)
 
     @classmethod
     def read_block(cls, block):
-        '''Read a block and return (header, tx_hashes, txs)'''
+        '''Return a tuple (header, tx_hashes, txs) given a raw block.'''
         header, rest = block[:cls.HEADER_LEN], block[cls.HEADER_LEN:]
         return (header, ) + Deserializer(rest).read_block()
 
     @classmethod
     def decimal_value(cls, value):
+        '''Return the number of standard coin units as a Decimal given a
+        quantity of smallest units.
+
+        For example 1 BTC is returned for 100 million satoshis.
+        '''
         return Decimal(value) / cls.VALUE_PER_COIN
 
 
@@ -167,6 +184,7 @@ class Bitcoin(Coin):
     TX_COUNT_HEIGHT = 420976
     TX_PER_BLOCK = 1600
 
+
 class BitcoinTestnet(Coin):
     NAME = "Bitcoin"
     SHORTNAME = "XTN"
@@ -177,6 +195,7 @@ class BitcoinTestnet(Coin):
     P2SH_VERBYTE = 0xc4
     WIF_BYTE = 0xef
 
+
 # Source: pycoin and others
 class Litecoin(Coin):
     NAME = "Litecoin"
@@ -188,6 +207,7 @@ class Litecoin(Coin):
     P2SH_VERBYTE = 0x05
     WIF_BYTE = 0xb0
 
+
 class LitecoinTestnet(Coin):
     NAME = "Litecoin"
     SHORTNAME = "XLT"
@@ -198,6 +218,7 @@ class LitecoinTestnet(Coin):
     P2SH_VERBYTE = 0xc4
     WIF_BYTE = 0xef
 
+
 # Source: namecoin.org
 class Namecoin(Coin):
     NAME = "Namecoin"
@@ -209,6 +230,7 @@ class Namecoin(Coin):
     P2SH_VERBYTE = 0x0d
     WIF_BYTE = 0xe4
 
+
 class NamecoinTestnet(Coin):
     NAME = "Namecoin"
     SHORTNAME = "XNM"
@@ -219,6 +241,7 @@ class NamecoinTestnet(Coin):
     P2SH_VERBYTE = 0xc4
     WIF_BYTE = 0xef
 
+
 # For DOGE there is disagreement across sites like bip32.org and
 # pycoin.  Taken from bip32.org and bitmerchant on github
 class Dogecoin(Coin):
@@ -231,6 +254,7 @@ class Dogecoin(Coin):
     P2SH_VERBYTE = 0x16
     WIF_BYTE = 0x9e
 
+
 class DogecoinTestnet(Coin):
     NAME = "Dogecoin"
     SHORTNAME = "XDT"
@@ -241,6 +265,7 @@ class DogecoinTestnet(Coin):
     P2SH_VERBYTE = 0xc4
     WIF_BYTE = 0xf1
 
+
 # Source: pycoin
 class Dash(Coin):
     NAME = "Dash"
@@ -252,6 +277,7 @@ class Dash(Coin):
     P2SH_VERBYTE = 0x10
     WIF_BYTE = 0xcc
 
+
 class DashTestnet(Coin):
     NAME = "Dogecoin"
     SHORTNAME = "tDASH"
diff --git a/lib/enum.py b/lib/enum.py
index e137c7f..920e038 100644
--- a/lib/enum.py
+++ b/lib/enum.py
@@ -1,8 +1,17 @@
-# enum-like type
-# From the Python Cookbook from http://code.activestate.com/recipes/67107/
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
+# and warranty status of this software.
 
+'''An enum-like type with reverse lookup.
 
-class EnumException(Exception):
+Source: Python Cookbook, http://code.activestate.com/recipes/67107/
+'''
+
+
+class EnumError(Exception):
     pass
 
 
@@ -20,13 +29,13 @@ class Enumeration:
             if isinstance(x, tuple):
                 x, i = x
             if not isinstance(x, str):
-                raise EnumException("enum name {} not a string".format(x))
+                raise EnumError("enum name {} not a string".format(x))
             if not isinstance(i, int):
-                raise EnumException("enum value {} not an integer".format(i))
+                raise EnumError("enum value {} not an integer".format(i))
             if x in uniqueNames:
-                raise EnumException("enum name {} not unique".format(x))
+                raise EnumError("enum name {} not unique".format(x))
             if i in uniqueValues:
-                raise EnumException("enum value {} not unique".format(x))
+                raise EnumError("enum value {} not unique".format(x))
             uniqueNames.add(x)
             uniqueValues.add(i)
             lookup[x] = i
diff --git a/lib/hash.py b/lib/hash.py
index bf0aed6..1563adc 100644
--- a/lib/hash.py
+++ b/lib/hash.py
@@ -1,6 +1,13 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Cryptograph hash functions and related classes.'''
+
+
 import hashlib
 import hmac
 
@@ -8,11 +15,13 @@ from lib.util import bytes_to_int, int_to_bytes
 
 
 def sha256(x):
+    '''Simple wrapper of hashlib sha256.'''
     assert isinstance(x, (bytes, bytearray, memoryview))
     return hashlib.sha256(x).digest()
 
 
 def ripemd160(x):
+    '''Simple wrapper of hashlib ripemd160.'''
     assert isinstance(x, (bytes, bytearray, memoryview))
     h = hashlib.new('ripemd160')
     h.update(x)
@@ -20,36 +29,41 @@ def ripemd160(x):
 
 
 def double_sha256(x):
+    '''SHA-256 of SHA-256, as used extensively in bitcoin.'''
     return sha256(sha256(x))
 
 
 def hmac_sha512(key, msg):
+    '''Use SHA-512 to provide an HMAC.'''
     return hmac.new(key, msg, hashlib.sha512).digest()
 
 
 def hash160(x):
+    '''RIPEMD-160 of SHA-256.
+
+    Used to make bitcoin addresses from pubkeys.'''
     return ripemd160(sha256(x))
 
+
 def hash_to_str(x):
-    '''Converts a big-endian binary hash to a little-endian hex string, as
-    shown in block explorers, etc.
+    '''Convert a big-endian binary hash to displayed hex string.
+
+    Display form of a binary hash is reversed and converted to hex.
     '''
     return bytes(reversed(x)).hex()
 
+
 def hex_str_to_hash(x):
-    '''Converts a little-endian hex string as shown to a big-endian binary
-    hash.'''
+    '''Convert a displayed hex string to a binary hash.'''
     return bytes(reversed(bytes.fromhex(x)))
 
-class InvalidBase58String(Exception):
-    pass
-
 
-class InvalidBase58CheckSum(Exception):
-    pass
+class Base58Error(Exception):
+    '''Exception used for Base58 errors.'''
 
 
 class Base58(object):
+    '''Class providing base 58 functionality.'''
 
     chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
     assert len(chars) == 58
@@ -59,17 +73,17 @@ class Base58(object):
     def char_value(c):
         val = Base58.cmap.get(c)
         if val is None:
-            raise InvalidBase58String
+            raise Base58Error('invalid base 58 character "{}"'.format(c))
         return val
 
     @staticmethod
     def decode(txt):
         """Decodes txt into a big-endian bytearray."""
         if not isinstance(txt, str):
-            raise InvalidBase58String("a string is required")
+            raise Base58Error('a string is required')
 
         if not txt:
-            raise InvalidBase58String("string cannot be empty")
+            raise Base58Error('string cannot be empty')
 
         value = 0
         for c in txt:
@@ -112,14 +126,14 @@ class Base58(object):
         be_bytes = Base58.decode(txt)
         result, check = be_bytes[:-4], be_bytes[-4:]
         if check != double_sha256(result)[:4]:
-            raise InvalidBase58CheckSum
+            raise Base58Error('invalid base 58 checksum for {}'.format(txt))
         return result
 
     @staticmethod
     def encode_check(payload):
         """Encodes a payload bytearray (which includes the version byte(s))
         into a Base58Check string."""
-        assert isinstance(payload, (bytes, bytearray))
+        assert isinstance(payload, (bytes, bytearray, memoryview))
 
         be_bytes = payload + double_sha256(payload)[:4]
         return Base58.encode(be_bytes)
diff --git a/lib/script.py b/lib/script.py
index 0239a1d..3894892 100644
--- a/lib/script.py
+++ b/lib/script.py
@@ -1,6 +1,13 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Script-related classes and functions.'''
+
+
 from binascii import hexlify
 import struct
 
@@ -10,7 +17,7 @@ from lib.util import cachedproperty
 
 
 class ScriptError(Exception):
-    pass
+    '''Exception used for script errors.'''
 
 
 OpCodes = Enumeration("Opcodes", [
@@ -52,7 +59,9 @@ assert OpCodes.OP_CHECKMULTISIG == 0xae
 
 
 class ScriptSig(object):
-    '''A script from a tx input, typically provides one or more signatures.'''
+    '''A script from a tx input.
+
+    Typically provides one or more signatures.'''
 
     SIG_ADDRESS, SIG_MULTI, SIG_PUBKEY, SIG_UNKNOWN = range(4)
 
@@ -73,8 +82,9 @@ class ScriptSig(object):
 
     @classmethod
     def from_script(cls, script, coin):
-        '''Returns an instance of this class.  Uncrecognised scripts return
-        an object of kind SIG_UNKNOWN.'''
+        '''Return an instance of this class.
+
+        Return an object with kind SIG_UNKNOWN for unrecognised scripts.'''
         try:
             return cls.parse_script(script, coin)
         except ScriptError:
@@ -82,8 +92,9 @@ class ScriptSig(object):
 
     @classmethod
     def parse_script(cls, script, coin):
-        '''Returns an instance of this class.  Raises on unrecognised
-        scripts.'''
+        '''Return an instance of this class.
+
+        Raises on unrecognised scripts.'''
         ops, datas = Script.get_ops(script)
 
         # Address, PubKey and P2SH redeems only push data
diff --git a/lib/tx.py b/lib/tx.py
index c45425c..7ea35f4 100644
--- a/lib/tx.py
+++ b/lib/tx.py
@@ -1,6 +1,13 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Transaction-related classes and functions.'''
+
+
 from collections import namedtuple
 import struct
 
@@ -9,6 +16,7 @@ from lib.hash import double_sha256, hash_to_str
 
 
 class Tx(namedtuple("Tx", "version inputs outputs locktime")):
+    '''Class representing a transaction.'''
 
     @cachedproperty
     def is_coinbase(self):
@@ -17,6 +25,7 @@ class Tx(namedtuple("Tx", "version inputs outputs locktime")):
     # FIXME: add hash as a cached property?
 
 class TxInput(namedtuple("TxInput", "prev_hash prev_idx script sequence")):
+    '''Class representing a transaction input.'''
 
     ZERO = bytes(32)
     MINUS_1 = 4294967295
@@ -41,6 +50,7 @@ class TxInput(namedtuple("TxInput", "prev_hash prev_idx script sequence")):
 
 
 class TxOutput(namedtuple("TxOutput", "value pk_script")):
+    '''Class representing a transaction output.'''
 
     @cachedproperty
     def pay_to(self):
@@ -48,9 +58,10 @@ class TxOutput(namedtuple("TxOutput", "value pk_script")):
 
 
 class Deserializer(object):
+    '''Deserializes blocks into transactions.'''
 
     def __init__(self, binary):
-        assert isinstance(binary, (bytes, memoryview))
+        assert isinstance(binary, bytes)
         self.binary = binary
         self.cursor = 0
 
diff --git a/lib/util.py b/lib/util.py
index 552a352..f59439b 100644
--- a/lib/util.py
+++ b/lib/util.py
@@ -1,6 +1,13 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Miscellaneous utility classes and functions.'''
+
+
 import array
 import logging
 import sys
@@ -72,6 +79,7 @@ def deep_getsizeof(obj):
 
 
 def chunks(items, size):
+    '''Break up items, an iterable, into chunks of length size.'''
     for i in range(0, len(items), size):
         yield items[i: i + size]
 
diff --git a/query.py b/query.py
index 57941fa..faea87a 100755
--- a/query.py
+++ b/query.py
@@ -1,8 +1,18 @@
 #!/usr/bin/env python3
-
-# See the file "LICENSE" for information about the copyright
+#
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Script to query the database for debugging purposes.
+
+Not currently documented; might become easier to use in future.
+'''
+
+
 import os
 import sys
 
diff --git a/server/block_processor.py b/server/block_processor.py
index aeaade9..ba42a0e 100644
--- a/server/block_processor.py
+++ b/server/block_processor.py
@@ -1,6 +1,13 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Block prefetcher and chain processor.'''
+
+
 import array
 import ast
 import asyncio
diff --git a/server/cache.py b/server/cache.py
index 0f0cc71..3adfbe8 100644
--- a/server/cache.py
+++ b/server/cache.py
@@ -1,6 +1,17 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''UTXO and file cache.
+
+During initial sync these cache data and only flush occasionally.
+Once synced flushes are performed after processing each block.
+'''
+
+
 import array
 import itertools
 import os
diff --git a/server/controller.py b/server/controller.py
index 5812f04..9d1cf64 100644
--- a/server/controller.py
+++ b/server/controller.py
@@ -1,6 +1,16 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Server controller.
+
+Coordinates the parts of the server.  Serves as a cache for
+client-serving data such as histories.
+'''
+
 import asyncio
 import signal
 import traceback
diff --git a/server/daemon.py b/server/daemon.py
index 96a07bc..aaef6c1 100644
--- a/server/daemon.py
+++ b/server/daemon.py
@@ -1,7 +1,11 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
-'''Classes for handling asynchronous connections to a blockchain
+'''Class for handling asynchronous connections to a blockchain
 daemon.'''
 
 import asyncio
diff --git a/server/env.py b/server/env.py
index 0a447ed..e27f570 100644
--- a/server/env.py
+++ b/server/env.py
@@ -1,6 +1,13 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Class for handling environment configuration and defaults.'''
+
+
 from os import environ
 
 from lib.coins import Coin
diff --git a/server/protocol.py b/server/protocol.py
index 04b4dcf..ebd8df7 100644
--- a/server/protocol.py
+++ b/server/protocol.py
@@ -1,6 +1,13 @@
-# See the file "LICENSE" for information about the copyright
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Classes for local RPC server and remote client TCP/SSL servers.'''
+
+
 import asyncio
 import codecs
 import json
diff --git a/server_main.py b/server_main.py
index 3a82c48..60948fa 100755
--- a/server_main.py
+++ b/server_main.py
@@ -1,8 +1,15 @@
 #!/usr/bin/env python3
-
-# See the file "LICENSE" for information about the copyright
+#
+# Copyright (c) 2016, Neil Booth
+#
+# All rights reserved.
+#
+# See the file "LICENCE" for information about the copyright
 # and warranty status of this software.
 
+'''Script to kick off the server.'''
+
+
 import asyncio
 import logging
 import os