diff --git a/gtsam/discrete/AlgebraicDecisionTree.h b/gtsam/discrete/AlgebraicDecisionTree.h
index 17a38f7cf3..637f56066f 100644
--- a/gtsam/discrete/AlgebraicDecisionTree.h
+++ b/gtsam/discrete/AlgebraicDecisionTree.h
@@ -29,7 +29,12 @@ namespace gtsam {
    */
   template<typename L>
   class GTSAM_EXPORT AlgebraicDecisionTree: public DecisionTree<L, double> {
-    /// Default method used by `formatter` when printing.
+    /**
+     * @brief Default method used by `labelFormatter` or `valueFormatter` when printing.
+     * 
+     * @param x The value passed to format.
+     * @return std::string 
+     */
     static std::string DefaultFormatter(const L& x) {
       std::stringstream ss;
       ss << x;
@@ -38,7 +43,7 @@ namespace gtsam {
 
    public:
 
-    typedef DecisionTree<L, double> Super;
+    using Base = DecisionTree<L, double>;
 
     /** The Real ring with addition and multiplication */
     struct Ring {
@@ -66,33 +71,33 @@ namespace gtsam {
     };
 
     AlgebraicDecisionTree() :
-        Super(1.0) {
+        Base(1.0) {
     }
 
-    AlgebraicDecisionTree(const Super& add) :
-        Super(add) {
+    AlgebraicDecisionTree(const Base& add) :
+        Base(add) {
     }
 
     /** Create a new leaf function splitting on a variable */
     AlgebraicDecisionTree(const L& label, double y1, double y2) :
-        Super(label, y1, y2) {
+        Base(label, y1, y2) {
     }
 
     /** Create a new leaf function splitting on a variable */
-    AlgebraicDecisionTree(const typename Super::LabelC& labelC, double y1, double y2) :
-        Super(labelC, y1, y2) {
+    AlgebraicDecisionTree(const typename Base::LabelC& labelC, double y1, double y2) :
+        Base(labelC, y1, y2) {
     }
 
     /** Create from keys and vector table */
     AlgebraicDecisionTree //
-    (const std::vector<typename Super::LabelC>& labelCs, const std::vector<double>& ys) {
-      this->root_ = Super::create(labelCs.begin(), labelCs.end(), ys.begin(),
+    (const std::vector<typename Base::LabelC>& labelCs, const std::vector<double>& ys) {
+      this->root_ = Base::create(labelCs.begin(), labelCs.end(), ys.begin(),
           ys.end());
     }
 
     /** Create from keys and string table */
     AlgebraicDecisionTree //
-    (const std::vector<typename Super::LabelC>& labelCs, const std::string& table) {
+    (const std::vector<typename Base::LabelC>& labelCs, const std::string& table) {
       // Convert string to doubles
       std::vector<double> ys;
       std::istringstream iss(table);
@@ -100,21 +105,27 @@ namespace gtsam {
           std::istream_iterator<double>(), std::back_inserter(ys));
 
       // now call recursive Create
-      this->root_ = Super::create(labelCs.begin(), labelCs.end(), ys.begin(),
+      this->root_ = Base::create(labelCs.begin(), labelCs.end(), ys.begin(),
           ys.end());
     }
 
     /** Create a new function splitting on a variable */
     template<typename Iterator>
     AlgebraicDecisionTree(Iterator begin, Iterator end, const L& label) :
-        Super(nullptr) {
+        Base(nullptr) {
       this->root_ = compose(begin, end, label);
     }
 
-    /** Convert */
+    /**
+     * Convert labels from type M to type L.
+     *
+     * @param other: The AlgebraicDecisionTree with label type M to convert.
+     * @param map: Map from label type M to label type L.
+     */
     template<typename M>
     AlgebraicDecisionTree(const AlgebraicDecisionTree<M>& other,
                           const std::map<M, L>& map) {
+      // Functor for label conversion so we can use `convertFrom`.
       std::function<L(const M&)> L_of_M = [&map](const M& label) -> L {
         return map.at(label);
       };
@@ -143,18 +154,18 @@ namespace gtsam {
     }
 
     /** sum out variable */
-    AlgebraicDecisionTree sum(const typename Super::LabelC& labelC) const {
+    AlgebraicDecisionTree sum(const typename Base::LabelC& labelC) const {
       return this->combine(labelC, &Ring::add);
     }
 
     /// print method customized to node type `double`.
     void print(const std::string& s,
-               const typename Super::LabelFormatter& labelFormatter =
+               const typename Base::LabelFormatter& labelFormatter =
                    &DefaultFormatter) const {
       auto valueFormatter = [](const double& v) {
         return (boost::format("%4.2g") % v).str();
       };
-      Super::print(s, labelFormatter, valueFormatter);
+      Base::print(s, labelFormatter, valueFormatter);
     }
 
     /// Equality method customized to node type `double`.
@@ -163,7 +174,7 @@ namespace gtsam {
       auto compare = [tol](double a, double b) {
         return std::abs(a - b) < tol;
       };
-      return Super::equals(other, compare);
+      return Base::equals(other, compare);
     }
   };
 // AlgebraicDecisionTree
diff --git a/gtsam/discrete/DecisionTree-inl.h b/gtsam/discrete/DecisionTree-inl.h
index 259489f069..0c016b6c54 100644
--- a/gtsam/discrete/DecisionTree-inl.h
+++ b/gtsam/discrete/DecisionTree-inl.h
@@ -82,13 +82,19 @@ namespace gtsam {
       return compare(this->constant_, other->constant_);
     }
 
-    /** print */
+    /**
+     * @brief Print method.
+     * 
+     * @param s Prefix string.
+     * @param labelFormatter Functor to format the node label.
+     * @param valueFormatter Functor to format the node value.
+     */
     void print(const std::string& s, const LabelFormatter& labelFormatter,
                const ValueFormatter& valueFormatter) const override {
       std::cout << s << " Leaf " << valueFormatter(constant_) << std::endl;
     }
 
-    /** to graphviz file */
+    /** Write graphviz format to stream `os`. */
     void dot(std::ostream& os, const LabelFormatter& labelFormatter,
              const ValueFormatter& valueFormatter,
              bool showZero) const override {
@@ -154,7 +160,7 @@ namespace gtsam {
     /** incremental allSame */
     size_t allSame_;
 
-    typedef boost::shared_ptr<const Choice> ChoicePtr;
+    using ChoicePtr = boost::shared_ptr<const Choice>;
 
   public:
 
@@ -462,6 +468,7 @@ namespace gtsam {
   template <typename X>
   DecisionTree<L, Y>::DecisionTree(const DecisionTree<L, X>& other,
                                    std::function<Y(const X&)> Y_of_X) {
+    // Define functor for identity mapping of node label.
     auto L_of_L = [](const L& label) { return label; };
     root_ = convertFrom<L, X>(Y_of_X, L_of_L);
   }
@@ -594,11 +601,11 @@ namespace gtsam {
       const typename DecisionTree<M, X>::NodePtr& f,
       std::function<L(const M&)> L_of_M,
       std::function<Y(const X&)> Y_of_X) const {
-    typedef DecisionTree<M, X> MX;
-    typedef typename MX::Leaf MXLeaf;
-    typedef typename MX::Choice MXChoice;
-    typedef typename MX::NodePtr MXNodePtr;
-    typedef DecisionTree<L, Y> LY;
+    using MX = DecisionTree<M, X>;
+    using MXLeaf = typename MX::Leaf;
+    using MXChoice = typename MX::Choice;
+    using MXNodePtr = typename MX::NodePtr;
+    using LY = DecisionTree<L, Y>;
 
     // ugliness below because apparently we can't have templated virtual functions
     // If leaf, apply unary conversion "op" and create a unique leaf
diff --git a/gtsam/discrete/DecisionTree.h b/gtsam/discrete/DecisionTree.h
index ecc3d17dce..6aa97d8ac4 100644
--- a/gtsam/discrete/DecisionTree.h
+++ b/gtsam/discrete/DecisionTree.h
@@ -39,6 +39,7 @@ namespace gtsam {
   template<typename L, typename Y>
   class GTSAM_EXPORT DecisionTree {
 
+   protected:
     /// Default method for comparison of two objects of type Y.
     static bool DefaultCompare(const Y& a, const Y& b) {
       return a == b;
@@ -51,11 +52,11 @@ namespace gtsam {
     using CompareFunc = std::function<bool(const Y&, const Y&)>;
 
     /** Handy typedefs for unary and binary function types */
-    typedef std::function<Y(const Y&)> Unary;
-    typedef std::function<Y(const Y&, const Y&)> Binary;
+    using Unary = std::function<Y(const Y&)>;
+    using Binary = std::function<Y(const Y&, const Y&)>;
 
     /** A label annotated with cardinality */
-    typedef std::pair<L,size_t> LabelC;
+    using LabelC = std::pair<L,size_t>;
 
     /** DTs consist of Leaf and Choice nodes, both subclasses of Node */
     class Leaf;
@@ -64,7 +65,7 @@ namespace gtsam {
     /** ------------------------ Node base class --------------------------- */
     class Node {
     public:
-      typedef boost::shared_ptr<const Node> Ptr;
+      using Ptr = boost::shared_ptr<const Node>;
 
 #ifdef DT_DEBUG_MEMORY
       static int nrNodes;
@@ -111,9 +112,9 @@ namespace gtsam {
   public:
 
     /** A function is a shared pointer to the root of a DT */
-    typedef typename Node::Ptr NodePtr;
+    using NodePtr = typename Node::Ptr;
 
-    /// a DecisionTree just contains the root. TODO(dellaert): make protected.
+    /// A DecisionTree just contains the root. TODO(dellaert): make protected.
     NodePtr root_;
 
   protected:
@@ -122,7 +123,16 @@ namespace gtsam {
     template<typename It, typename ValueIt>
     NodePtr create(It begin, It end, ValueIt beginY, ValueIt endY) const;
 
-    /// Convert from a DecisionTree<M, X>.
+    /**
+     * @brief Convert from a DecisionTree<M, X> to DecisionTree<L, Y>.
+     * 
+     * @tparam M The previous label type.
+     * @tparam X The previous node type.
+     * @param f The node pointer to the root of the previous DecisionTree.
+     * @param L_of_M Functor to convert from label type M to type L.
+     * @param Y_of_X Functor to convert from node type X to type Y.
+     * @return NodePtr 
+     */
     template <typename M, typename X>
     NodePtr convertFrom(const typename DecisionTree<M, X>::NodePtr& f,
                         std::function<L(const M&)> L_of_M,
@@ -159,12 +169,27 @@ namespace gtsam {
     DecisionTree(const L& label, //
         const DecisionTree& f0, const DecisionTree& f1);
 
-    /** Convert from a different type. */
+    /**
+     * @brief Convert from a different node type.
+     *
+     * @tparam X The previous node type.
+     * @param other The DecisionTree to convert from.
+     * @param Y_of_X Functor to convert from node type X to type Y.
+     */
     template <typename X>
     DecisionTree(const DecisionTree<L, X>& other,
                  std::function<Y(const X&)> Y_of_X);
 
-    /** Convert from a different type, also transate labels via map. */
+    /**
+     * @brief Convert from a different node type X to node type Y, also transate
+     * labels via map from type M to L.
+     *
+     * @tparam M Previous label type.
+     * @tparam X Previous node type.
+     * @param other The decision tree to convert.
+     * @param L_of_M Map from label type M to type L.
+     * @param Y_of_X Functor to convert from type X to type Y.
+     */
     template <typename M, typename X>
     DecisionTree(const DecisionTree<M, X>& other, const std::map<M, L>& L_of_M,
                  std::function<Y(const X&)> Y_of_X);
@@ -173,7 +198,13 @@ namespace gtsam {
     /// @name Testable
     /// @{
 
-    /** GTSAM-style print */
+    /**
+     * @brief GTSAM-style print
+     * 
+     * @param s Prefix string.
+     * @param labelFormatter Functor to format the node label.
+     * @param valueFormatter Functor to format the node value.
+     */
     void print(const std::string& s, const LabelFormatter& labelFormatter,
                const ValueFormatter& valueFormatter) const;
 
@@ -189,7 +220,7 @@ namespace gtsam {
     virtual ~DecisionTree() {
     }
 
-    /** empty tree? */
+    /// Check if tree is empty.
     bool empty() const { return !root_; }
 
     /** equality */
@@ -248,18 +279,21 @@ namespace gtsam {
 
   /** free versions of apply */
 
+  /// Apply unary operator `op` to DecisionTree `f`.
   template<typename L, typename Y>
   DecisionTree<L, Y> apply(const DecisionTree<L, Y>& f,
       const typename DecisionTree<L, Y>::Unary& op) {
     return f.apply(op);
   }
 
+  /// Apply unary operator `op` to DecisionTree `f` but with node type.
   template<typename L, typename Y, typename X>
   DecisionTree<L, Y> apply(const DecisionTree<L, Y>& f,
       const std::function<Y(const X&)>& op) {
     return f.apply(op);
   }
 
+  /// Apply binary operator `op` to DecisionTree `f`.
   template<typename L, typename Y>
   DecisionTree<L, Y> apply(const DecisionTree<L, Y>& f,
       const DecisionTree<L, Y>& g,
diff --git a/gtsam/discrete/tests/testDecisionTree.cpp b/gtsam/discrete/tests/testDecisionTree.cpp
index cc61a382f9..53f3c43797 100644
--- a/gtsam/discrete/tests/testDecisionTree.cpp
+++ b/gtsam/discrete/tests/testDecisionTree.cpp
@@ -45,15 +45,6 @@ struct Crazy {
   double b;
 };
 
-//   bool equals(const Crazy& other, double tol = 1e-12) const {
-//     return a == other.a && std::abs(b - other.b) < tol;
-//   }
-
-//   bool operator==(const Crazy& other) const {
-//     return this->equals(other);
-//   }
-// };
-
 struct CrazyDecisionTree : public DecisionTree<string, Crazy> {
   /// print to stdout
   void print(const std::string& s = "") const {
@@ -261,8 +252,6 @@ TEST(DT, conversion)
     return y != 0;
   };
   BDT f2(f1, ordering, bool_of_int);
-  //  f1.print("f1");
-  //  f2.print("f2");
 
   // create a value
   Assignment<Label> x00, x01, x10, x11;