diff --git a/cpp/BTree.h b/cpp/BTree.h
index 206d0bc89..1513ba9ab 100644
--- a/cpp/BTree.h
+++ b/cpp/BTree.h
@@ -6,6 +6,8 @@
 #include <boost/shared_ptr.hpp>
 #include <CppUnitLite/TestHarness.h>
 #include "Key.h"
+#include <iostream>
+#include <sstream>
 
 //    type 'a t =
 //        Empty
@@ -105,13 +107,48 @@ typename Node<Key, Value>::Tree add(const Key& key, const Value& value, const ty
 }
 
 template <class Key, class Value>
-Value find(const typename boost::shared_ptr<Node<Key,Value> >& tree, const Key& key){
+boost::optional<Value> find(const typename boost::shared_ptr<Node<Key,Value> >& tree, const Key& key){
   if(tree->key_ == key)
   	return tree->value_;
-  if(key < tree->key_)
+  if(key < tree->key_ && tree->left_ != NULL)
   	return find(tree->left_, key);
-  else
+  else if(tree->right_ != NULL)
   	return find(tree->right_,key);
+  return boost::none;
+}
+
+template <class Key, class Value>
+typename Node<Key, Value>::Tree begin(const typename Node<Key,Value>::Tree& tree) {
+	if(tree->left_ !=NULL){
+		return begin(tree->left_);
+	}
+	else {
+		return tree;
+	}
+}
+
+template <class Key, class Value>
+typename Node<Key, Value>::Tree end(const typename Node<Key,Value>::Tree& tree) {
+	if(tree->right_ !=NULL){
+		return begin(tree->right_);
+	}
+	else {
+		return tree;
+	}
+}
+
+template <class Key, class Value>
+void walk(const typename boost::shared_ptr<Node<Key,Value> >& tree, std::string s) {
+	if(tree->left_ !=NULL) {
+		walk(tree->left_, s+"->l");
+	}
+	Key k = tree->key_;
+	std::stringstream ss;
+	ss << tree->height_;
+	k.print(ss.str() +" "+ s);
+	if(tree->right_ !=NULL) {
+		walk(tree->right_, s+"->r");
+	}
 }
 
 }
diff --git a/cpp/testBTree.cpp b/cpp/testBTree.cpp
new file mode 100644
index 000000000..93c33b3ab
--- /dev/null
+++ b/cpp/testBTree.cpp
@@ -0,0 +1,55 @@
+/*
+ * testBNode.cpp
+ *
+ *  Created on: Feb 3, 2010
+ *      Author: cbeall3
+ */
+
+#include <boost/shared_ptr.hpp>
+#include <CppUnitLite/TestHarness.h>
+#include "Key.h"
+#include "BTree.h"
+
+using namespace std;
+using namespace gtsam;
+
+typedef pair<size_t, size_t> Range;
+//typedef boost::shared_ptr<Node<Symbol, Range> > Tree;
+typedef Node<Symbol,Range>::Tree RangeTree;
+
+
+/* ************************************************************************* */
+TEST( BNode, constructor )
+{
+	RangeTree tree;
+	CHECK(tree==NULL)
+	LONGS_EQUAL(0,height(tree))
+
+	// check the height of tree after adding an element
+	RangeTree tree1 = add(Symbol('x',1), Range(1,2), tree);
+  LONGS_EQUAL(1,height(tree1))
+
+	boost::optional<Range> range1 = find(tree1, Symbol('x',1));
+  CHECK(range1 == Range(1,2));
+
+  RangeTree tree2 = add(Symbol('x',5), Range(5,6), tree1);
+  RangeTree tree3 = add(Symbol('x',3), Range(3,4), tree2);
+
+  boost::optional<Range> range2 = find(tree3, Symbol('x',5));
+  boost::optional<Range> range3 = find(tree3, Symbol('x',3));
+
+	CHECK(range2 == Range(5,6));
+	CHECK(range3 == Range(3,4));
+
+	// this causes Bus Error.
+	//RangeTree tree4 = add(Symbol('x',2), Range(3,4), tree3);
+
+	//walk(tree4, "root");
+}
+
+/* ************************************************************************* */
+int main() {
+	TestResult tr;
+	return TestRegistry::runAllTests(tr);
+}
+/* ************************************************************************* */