diff --git a/Ledger.hs b/Ledger.hs
index 33f6a1aa9..4256f67fc 100644
--- a/Ledger.hs
+++ b/Ledger.hs
@@ -1,5 +1,10 @@
 {-| 
+
+The Ledger package allows parsing and querying of ledger files.
+It generally provides a compatible subset of C++ ledger's functionality.
+
 -}
+
 module Ledger (
                module Ledger.Types,
                module Ledger.Currency,
diff --git a/Ledger/Account.hs b/Ledger/Account.hs
index 4b365fd6b..81e4ae09e 100644
--- a/Ledger/Account.hs
+++ b/Ledger/Account.hs
@@ -1,3 +1,11 @@
+{-|
+
+An 'Account' stores an account name, all transactions in the account
+(excluding any subaccounts), and the total balance (including any
+subaccounts).
+
+-}
+
 module Ledger.Account
 where
 import Ledger.Utils
diff --git a/Ledger/AccountName.hs b/Ledger/AccountName.hs
index a85c97bc6..ef40c0cf8 100644
--- a/Ledger/AccountName.hs
+++ b/Ledger/AccountName.hs
@@ -1,3 +1,10 @@
+{-|
+
+'AccountName's are strings like @assets:cash:petty@.
+From a set of these we derive the account hierarchy.
+
+-}
+
 module Ledger.AccountName
 where
 import Ledger.Utils
@@ -49,8 +56,8 @@ subAccountNamesFrom accts a = filter (`isSubAccountNameOf` a) accts
 -- | We could almost get by with just the AccountName manipulations
 -- above, but we need smarter structures to eg display the account
 -- tree with boring accounts elided.  This converts a list of
--- AccountNames to a tree (later we will convert that to a tree of
--- Accounts.)
+-- AccountName to a tree (later we will convert that to a tree of
+-- 'Account'.)
 accountNameTreeFrom_props =
     [
      accountNameTreeFrom ["a"]       == Node "top" [Node "a" []],
diff --git a/Ledger/Amount.hs b/Ledger/Amount.hs
index cdf39fd31..132a2f22a 100644
--- a/Ledger/Amount.hs
+++ b/Ledger/Amount.hs
@@ -1,5 +1,7 @@
 {-|
-A simple amount is a currency, quantity pair:
+An 'Amount' is some quantity of money, shares, or anything else.
+
+A simple amount is a currency, quantity pair (where currency can be anything):
 
 @
   $1 
@@ -7,11 +9,11 @@ A simple amount is a currency, quantity pair:
   EUR 3.44 
   GOOG 500
   1.5h
-  90m
+  90apples
   0 
 @
 
-A mixed amount is one or more simple amounts:
+A mixed amount (not yet implemented) is one or more simple amounts:
 
 @
   $50, EUR 3, AAPL 500
diff --git a/Ledger/Currency.hs b/Ledger/Currency.hs
index 3284e627d..55a6607dd 100644
--- a/Ledger/Currency.hs
+++ b/Ledger/Currency.hs
@@ -1,3 +1,10 @@
+{-|
+
+A 'Currency' is a symbol and a conversion rate relative to the
+dollar. Currency symbols are parsed from the ledger file, rates are
+currently hard-coded.
+
+-}
 module Ledger.Currency
 where
 import qualified Data.Map as Map
diff --git a/Ledger/Ledger.hs b/Ledger/Ledger.hs
index 35b94f451..e9dea4efc 100644
--- a/Ledger/Ledger.hs
+++ b/Ledger/Ledger.hs
@@ -1,3 +1,10 @@
+{-|
+
+A 'Ledger' stores, for efficiency, a 'RawLedger' plus its tree of account
+names, a map from account names to 'Account's, and the display precision.
+
+-}
+
 module Ledger.Ledger
 where
 import qualified Data.Map as Map
diff --git a/Ledger/LedgerEntry.hs b/Ledger/LedgerEntry.hs
index 937c95096..a0a88ba72 100644
--- a/Ledger/LedgerEntry.hs
+++ b/Ledger/LedgerEntry.hs
@@ -1,3 +1,10 @@
+{-|
+
+A 'LedgerEntry' represents a normal entry in the ledger file. It contains
+two or more 'RawTransaction's which balance.
+
+-}
+
 module Ledger.LedgerEntry
 where
 import Ledger.Utils
diff --git a/Ledger/RawLedger.hs b/Ledger/RawLedger.hs
index 89eac41b5..91d930464 100644
--- a/Ledger/RawLedger.hs
+++ b/Ledger/RawLedger.hs
@@ -1,3 +1,10 @@
+{-|
+
+A 'RawLedger' is a parsed ledger file. We call it raw to distinguish from
+the cached 'Ledger'.
+
+-}
+
 module Ledger.RawLedger
 where
 import qualified Data.Map as Map
diff --git a/Ledger/RawTransaction.hs b/Ledger/RawTransaction.hs
index aa01f3dc4..c285e7ae3 100644
--- a/Ledger/RawTransaction.hs
+++ b/Ledger/RawTransaction.hs
@@ -1,3 +1,10 @@
+{-|
+
+A 'RawTransaction' represents a single transaction line within a ledger
+entry. We call it raw to distinguish from the cached 'Transaction'.
+
+-}
+
 module Ledger.RawTransaction
 where
 import Ledger.Utils
diff --git a/Ledger/TimeLog.hs b/Ledger/TimeLog.hs
index 669bf60c5..7d6545f43 100644
--- a/Ledger/TimeLog.hs
+++ b/Ledger/TimeLog.hs
@@ -1,3 +1,10 @@
+{-|
+
+A 'TimeLog' is a parsed timelog file (generated by timeclock.el).
+It contains zero or more 'TimeLogEntry's.
+
+-}
+
 module Ledger.TimeLog
 where
 import Ledger.Utils
diff --git a/Ledger/Transaction.hs b/Ledger/Transaction.hs
index 901a9aa0f..4eb8713dd 100644
--- a/Ledger/Transaction.hs
+++ b/Ledger/Transaction.hs
@@ -1,3 +1,10 @@
+{-|
+
+A 'Transaction' is a 'RawTransaction' with its parent 'LedgerEntry' \'s
+date and description attached, for easier querying.
+
+-}
+
 module Ledger.Transaction
 where
 import Ledger.Utils
@@ -13,7 +20,9 @@ instance Show Transaction where
     show (Transaction eno d desc a amt) = 
         unwords [d,desc,a,show amt]
 
--- | we use the entry number e to remember the grouping of txns
+-- | Convert a 'LedgerEntry' to two or more 'Transaction's. An id number
+-- is attached to the transactions to preserve their grouping - it should
+-- be unique per entry.
 flattenEntry :: (LedgerEntry, Int) -> [Transaction]
 flattenEntry (LedgerEntry d _ _ desc _ ts _, e) = 
     [Transaction e d desc (taccount t) (tamount t) | t <- ts]
diff --git a/Ledger/Types.hs b/Ledger/Types.hs
index 03f401d42..d52f694b7 100644
--- a/Ledger/Types.hs
+++ b/Ledger/Types.hs
@@ -1,36 +1,32 @@
-{-| 
+{-|
+
 All the main data types, defined here to avoid import cycles.
+See the corresponding modules for documentation.
+
 -}
+
 module Ledger.Types 
 where
 import Ledger.Utils
 import qualified Data.Map as Map
 
--- | a date
 type Date = String
 
--- | a date and time
 type DateTime = String
 
--- | the currency of an Amount.
 data Currency = Currency {
       symbol :: String,
-      rate :: Double  -- ^ relative to the dollar (rates are currently hardcoded)
+      rate :: Double
     } deriving (Eq,Show)
 
--- | some amount of money, shares, or anything else.
 data Amount = Amount {
       currency :: Currency,
       quantity :: Double,
       precision :: Int           -- ^ number of significant decimal places
     } deriving (Eq)
 
--- | AccountNames are strings like @assets:cash:petty@, from which we derive
--- the chart of accounts
 type AccountName = String
 
--- | a single transaction line within a ledger entry. We call it raw to
--- distinguish from the cached 'Transaction'.
 data RawTransaction = RawTransaction {
       taccount :: AccountName,
       tamount :: Amount,
@@ -49,7 +45,6 @@ data PeriodicEntry = PeriodicEntry {
       p_transactions :: [RawTransaction]
     } deriving (Eq)
 
--- | a regular ledger entry, containing two or more transactions which balance
 data LedgerEntry = LedgerEntry {
       edate :: Date,
       estatus :: Bool,
@@ -60,8 +55,6 @@ data LedgerEntry = LedgerEntry {
       epreceding_comment_lines :: String
     } deriving (Eq)
 
--- | a parsed ledger file. We call it raw to distinguish from the cached
--- 'Ledger'.
 data RawLedger = RawLedger {
       modifier_entries :: [ModifierEntry],
       periodic_entries :: [PeriodicEntry],
@@ -69,22 +62,16 @@ data RawLedger = RawLedger {
       final_comment_lines :: String
     } deriving (Eq)
 
--- | a timelog entry in a timelog file (generated by timeclock.el)
 data TimeLogEntry = TimeLogEntry {
       tlcode :: Char,
       tldatetime :: DateTime,
       tlcomment :: String
     } deriving (Eq,Ord)
 
--- | a parsed timelog file
 data TimeLog = TimeLog {
       timelog_entries :: [TimeLogEntry]
     } deriving (Eq)
 
--- | optimisations: these types provide some caching and are easier to work with.
--- 
--- A Transaction is a RawTransaction with some of its parent
--- LedgerEntry's data attached.
 data Transaction = Transaction {
       entryno :: Int,
       date :: Date,
@@ -93,16 +80,12 @@ data Transaction = Transaction {
       amount :: Amount
     } deriving (Eq)
 
--- | an Account stores an account name, all transactions in the account
--- (excluding subaccounts), and the total balance (including subaccounts).
 data Account = Account {
       aname :: AccountName,
       atransactions :: [Transaction],
       abalance :: Amount
     }
 
--- | a raw ledger plus its tree of account names, a map from account names
--- to Accounts, and the preferred precision.
 data Ledger = Ledger {
       rawledger :: RawLedger,
       accountnametree :: Tree AccountName,
diff --git a/Ledger/Utils.hs b/Ledger/Utils.hs
index b0f6a5469..9bb60f464 100644
--- a/Ledger/Utils.hs
+++ b/Ledger/Utils.hs
@@ -1,4 +1,9 @@
--- standard always-available imports and utilities
+{-|
+
+Standard always-available imports and utilities.
+
+-}
+
 module Ledger.Utils (
               module Ledger.Utils,
               module Char,
diff --git a/Options.hs b/Options.hs
index df149cb6e..e1ccd6826 100644
--- a/Options.hs
+++ b/Options.hs
@@ -93,7 +93,7 @@ wildcard :: Regex
 wildcard = mkRegex ".*"
 
 -- | parse the user's specified ledger file and do some action with it
--- (or report a parse error)
+-- (or report a parse error). This function makes the whole thing go.
 parseLedgerAndDo :: [Flag] -> (Regex,Regex) -> (Ledger -> IO ()) -> IO ()
 parseLedgerAndDo opts pats cmd = do
     path <- ledgerFilePath opts