diff --git a/src/ripple_app/ledger/LedgerHistory.cpp b/src/ripple_app/ledger/LedgerHistory.cpp
index fee648bb5..4791d7a08 100644
--- a/src/ripple_app/ledger/LedgerHistory.cpp
+++ b/src/ripple_app/ledger/LedgerHistory.cpp
@@ -86,6 +86,7 @@ Ledger::pointer LedgerHistory::getLedgerBySeq (std::uint32_t index)
     assert (ret->getLedgerSeq () == index);
 
     {
+        // Add this ledger to the local tracking by index
         LedgersByHash::ScopedLockType sl (m_ledgers_by_hash.peekMutex ());
 
         assert (ret->isImmutable ());
@@ -127,7 +128,7 @@ void LedgerHistory::builtLedger (Ledger::ref ledger)
     ConsensusValidated::ScopedLockType sl (
         m_consensus_validated.peekMutex());
 
-    boost::shared_ptr< std::pair< LedgerHash, LedgerHash > > entry = boost::make_shared<std::pair< LedgerHash, LedgerHash >>();
+    auto entry = boost::make_shared<std::pair< LedgerHash, LedgerHash >>();
     m_consensus_validated.canonicalize(index, entry, false);
 
     if (entry->first != hash)
diff --git a/src/ripple_app/ledger/LedgerHistory.h b/src/ripple_app/ledger/LedgerHistory.h
index d55153a47..149659c88 100644
--- a/src/ripple_app/ledger/LedgerHistory.h
+++ b/src/ripple_app/ledger/LedgerHistory.h
@@ -23,35 +23,70 @@
 namespace ripple {
 
 // VFALCO TODO Rename to OldLedgers ?
+
+/** Retains historical ledgers. */
 class LedgerHistory : beast::LeakChecked <LedgerHistory>
 {
 public:
     LedgerHistory ();
 
+    /** Track a ledger
+        @return `true` if the ledger was already tracked
+    */
     bool addLedger (Ledger::pointer ledger, bool validated);
 
+    /** Get the ledgers_by_hash cache hit rate
+        @return the hit rate
+    */
     float getCacheHitRate ()
     {
         return m_ledgers_by_hash.getHitRate ();
     }
 
+    /** Get a ledger given its squence number
+        @param ledgerIndex The sequence number of the desired ledger
+    */
     Ledger::pointer getLedgerBySeq (LedgerIndex ledgerIndex);
 
+    /** Get a ledger's hash given its sequence number
+        @param ledgerIndex The sequence number of the desired ledger
+        @return The hash of the specified ledger
+    */
     LedgerHash getLedgerHash (LedgerIndex ledgerIndex);
 
+    /** Retrieve a ledger given its hash
+        @param ledgerHash The hash of the requested ledger
+        @return The ledger requested
+    */
     Ledger::pointer getLedgerByHash (LedgerHash const& ledgerHash);
 
+    /** Set the history cache's paramters
+        @param size The target size of the cache
+        @param age The target age of the cache, in seconds
+    */
     void tune (int size, int age);
 
+    /** Remove stale cache entries
+    */
     void sweep ()
     {
         m_ledgers_by_hash.sweep ();
         m_consensus_validated.sweep ();
     }
 
+    /** Report that we have locally built a particular ledger
+    */
     void builtLedger (Ledger::ref);
+
+    /** Report that we have validated a particular ledger
+    */
     void validatedLedger (Ledger::ref);
 
+    /** Repair a hash to index mapping
+        @param ledgerIndex The index whose mapping is to be repaired
+        @param ledgerHash The hash it is to be mapped to
+        @return `true` if the mapping was repaired
+    */
     bool fixIndex(LedgerIndex ledgerIndex, LedgerHash const& ledgerHash);
 
 private:
@@ -59,7 +94,10 @@ private:
 
     LedgersByHash m_ledgers_by_hash;
 
-    //typedef std::pair <LedgerHash, LedgerHash>
+    // Maps ledger indexes to the corresponding hashes
+    // For debug and logging purposes
+    // 1) The hash of a ledger with that index we build
+    // 2) The hash of a ledger with that index we validated
     typedef TaggedCache <LedgerIndex,
         std::pair< LedgerHash, LedgerHash >> ConsensusValidated;
     ConsensusValidated m_consensus_validated;