diff --git a/lib/rational.rb b/lib/rational.rb
index 69a3b76..9deed09 100644
--- a/lib/rational.rb
+++ b/lib/rational.rb
@@ -7,6 +7,8 @@
 #
 # Documentation by Kevin Jackson and Gavin Sinclair.
 # 
+# Performance improvements by Kurt Stephens.
+#
 # When you <tt>require 'rational'</tt>, all interactions between numbers
 # potentially return a rational result.  For example:
 #
@@ -104,13 +106,8 @@ class Rational < Numeric
       num = -num
       den = -den
     end
-    if num.kind_of?(Integer) and den.kind_of?(Integer)
-      @numerator = num
-      @denominator = den
-    else
-      @numerator = num.to_i
-      @denominator = den.to_i
-    end
+    @numerator = num.to_i
+    @denominator = den.to_i
   end
 
   #
@@ -122,14 +119,13 @@ class Rational < Numeric
   #   r + 0.5                # -> 1.25
   #
   def + (a)
-    if a.kind_of?(Rational)
-      num = @numerator * a.denominator
-      num_a = a.numerator * @denominator
-      Rational(num + num_a, @denominator * a.denominator)
-    elsif a.kind_of?(Integer)
-      self + Rational.new!(a, 1)
-    elsif a.kind_of?(Float)
-      Float(self) + a
+    case a
+    when Rational # => Rational | Integer
+      Rational(       (@numerator * a.denominator) + (a.numerator * @denominator), @denominator * a.denominator)
+    when Integer  # => Rational
+      Rational.reduce((@numerator                ) + (a           * @denominator), @denominator)
+    when Float
+      self.to_f + a
     else
       x, y = a.coerce(self)
       x + y
@@ -146,14 +142,13 @@ class Rational < Numeric
   #   r - 0.5              # -> 0.25
   #
   def - (a)
-    if a.kind_of?(Rational)
-      num = @numerator * a.denominator
-      num_a = a.numerator * @denominator
-      Rational(num - num_a, @denominator*a.denominator)
-    elsif a.kind_of?(Integer)
-      self - Rational.new!(a, 1)
-    elsif a.kind_of?(Float)
-      Float(self) - a
+    case a
+    when Rational # => Rational | Integer
+      Rational(       (@numerator * a.denominator) - (a.numerator * @denominator), @denominator * a.denominator)
+    when Integer  # => Rational
+      Rational.reduce((@numerator                ) - (a           * @denominator), @denominator)
+    when Float
+      self.to_f - a
     else
       x, y = a.coerce(self)
       x - y
@@ -161,6 +156,13 @@ class Rational < Numeric
   end
 
   #
+  # Unary Minus--Returns the receiver's value, negated.
+  #
+  def -@
+    Rational.new!(- @numerator, @denominator)
+  end
+
+  #
   # Returns the product of this value and +a+.
   #
   # Examples:
@@ -171,14 +173,13 @@ class Rational < Numeric
   #   r * Rational(1,2)    # -> Rational(3,8)
   #
   def * (a)
-    if a.kind_of?(Rational)
-      num = @numerator * a.numerator
-      den = @denominator * a.denominator
-      Rational(num, den)
-    elsif a.kind_of?(Integer)
-      self * Rational.new!(a, 1)
-    elsif a.kind_of?(Float)
-      Float(self) * a
+    case a
+    when Rational
+      Rational(@numerator * a.numerator, @denominator * a.denominator)
+    when Integer
+      Rational(@numerator * a          , @denominator)
+    when Float
+      self.to_f * a
     else
       x, y = a.coerce(self)
       x * y
@@ -193,15 +194,14 @@ class Rational < Numeric
   #   r / Rational(1,2)    # -> Rational(3,2)
   #
   def / (a)
-    if a.kind_of?(Rational)
-      num = @numerator * a.denominator
-      den = @denominator * a.numerator
-      Rational(num, den)
-    elsif a.kind_of?(Integer)
+    case a
+    when Rational
+      Rational(@numerator * a.denominator, @denominator * a.numerator)
+    when Integer
       raise ZeroDivisionError, "division by zero" if a == 0
-      self / Rational.new!(a, 1)
-    elsif a.kind_of?(Float)
-      Float(self) / a
+      Rational(@numerator                , @denominator * a          )
+    when Float
+      self.to_f / a
     else
       x, y = a.coerce(self)
       x / y
@@ -218,22 +218,17 @@ class Rational < Numeric
   #   r ** Rational(1,2)   # -> 0.866025403784439
   #
   def ** (other)
-    if other.kind_of?(Rational)
-      Float(self) ** other
-    elsif other.kind_of?(Integer)
+    case other
+    when Rational, Float
+      self.to_f ** other
+    when Integer
       if other > 0
-	num = @numerator ** other
-	den = @denominator ** other
+	Rational.new!(@numerator ** other, @denominator ** other)
       elsif other < 0
-	num = @denominator ** -other
-	den = @numerator ** -other
-      elsif other == 0
-	num = 1
-	den = 1
+	Rational.new!(@denominator ** -other, @numerator ** -other)
+      else
+	Rational.new!(1, 1) # why not Fixnum 1?
       end
-      Rational.new!(num, den)
-    elsif other.kind_of?(Float)
-      Float(self) ** other
     else
       x, y = other.coerce(self)
       x ** y
@@ -256,7 +251,7 @@ class Rational < Numeric
   #
   def % (other)
     value = (self / other).floor
-    return self - other * value
+    self - other * value
   end
 
   #
@@ -268,7 +263,7 @@ class Rational < Numeric
   #
   def divmod(other)
     value = (self / other).floor
-    return value, self - other * value
+    [ value, self - other * value ]
   end
 
   #
@@ -282,6 +277,17 @@ class Rational < Numeric
     end
   end
 
+  # Returns true or false.
+  def zero?
+    @numerator.zero?
+  end
+
+  # See Numeric#nonzero?
+  def nonzero?
+    @numerator.nonzero? ? self : nil
+  end
+
+
   #
   # Returns +true+ iff this value is numerically equal to +other+.
   #
@@ -292,12 +298,13 @@ class Rational < Numeric
   # Don't use Rational.new!
   #
   def == (other)
-    if other.kind_of?(Rational)
+    case other
+    when Rational
       @numerator == other.numerator and @denominator == other.denominator
-    elsif other.kind_of?(Integer)
-      self == Rational.new!(other, 1)
-    elsif other.kind_of?(Float)
-      Float(self) == other
+    when Integer
+      @numerator == other && @denominator == 1
+    when Float
+      self.to_f == other
     else
       other == self
     end
@@ -307,34 +314,27 @@ class Rational < Numeric
   # Standard comparison operator.
   #
   def <=> (other)
-    if other.kind_of?(Rational)
-      num = @numerator * other.denominator
-      num_a = other.numerator * @denominator
-      v = num - num_a
-      if v > 0
-	return 1
-      elsif v < 0
-	return  -1
-      else
-	return 0
-      end
-    elsif other.kind_of?(Integer)
-      return self <=> Rational.new!(other, 1)
-    elsif other.kind_of?(Float)
-      return Float(self) <=> other
-    elsif defined? other.coerce
-      x, y = other.coerce(self)
-      return x <=> y
+    case other
+    when Rational
+      ((@numerator * other.denominator) <=> (other.numerator * @denominator))
+    when Integer
+      ((@numerator                    ) <=> (other           * @denominator))
+    when Float
+      self.to_f <=> other
     else
-      return nil
+      if defined? other.coerce
+        x, y = other.coerce(self)
+        x <=> y
+      end # nil
     end
   end
 
   def coerce(other)
-    if other.kind_of?(Float)
-      return other, self.to_f
-    elsif other.kind_of?(Integer)
-      return Rational.new!(other, 1), self
+    case other
+    when Float
+      [ other, self.to_f ]
+    when Integer
+      [ Rational.new!(other, 1), self ]
     else
       super
     end
@@ -363,23 +363,19 @@ class Rational < Numeric
 
   def truncate()
     if @numerator < 0
-      return -((-@numerator).div(@denominator))
+      -((-@numerator).div(@denominator))
+    else
+      @numerator.div(@denominator)
     end
-    @numerator.div(@denominator)
   end
 
   alias_method :to_i, :truncate
 
   def round()
     if @numerator < 0
-      num = -@numerator
-      num = num * 2 + @denominator
-      den = @denominator * 2
-      -(num.div(den))
+      -((@numerator * -2 + @denominator).div(@denominator * 2))
     else
-      num = @numerator * 2 + @denominator
-      den = @denominator * 2
-      num.div(den)
+      ((@numerator * 2 + @denominator).div(@denominator * 2))
     end
   end
 
@@ -401,7 +397,7 @@ class Rational < Numeric
     if @denominator == 1
       @numerator.to_s
     else
-      @numerator.to_s+"/"+@denominator.to_s
+      "#{@numerator}/#{@denominator}"
     end
   end
 
@@ -418,7 +414,7 @@ class Rational < Numeric
   #   Rational(5,8).inspect     # -> "Rational(5, 8)"
   #
   def inspect
-    sprintf("Rational(%s, %s)", @numerator.inspect, @denominator.inspect)
+    "Rational(#{@numerator.inspect}, #{@denominator.inspect})"
   end
 
   #
diff --git a/numeric.c b/numeric.c
index 634c2eb..e19deb6 100644
--- a/numeric.c
+++ b/numeric.c
@@ -3022,6 +3022,30 @@ fix_even_p(VALUE num)
     return Qtrue;
 }
 
+static VALUE
+fix_gcd(int argc, VALUE *argv, VALUE self) {
+  if ( argc != 1 ) {
+    rb_raise(rb_eArgError, "wrong number of arguments (%d for %d)", argc, 1);
+  }
+  /* Handle Fixnum#gcd(Fixnum) here. */
+  if ( FIXNUM_P(argv[0]) ) {
+    /* fprintf(stderr, "Using Fixnum#gcd(Fixnum)\n"); */
+    long a = FIX2LONG(self);
+    long b = FIX2LONG(argv[0]);
+    long min = a < 0 ? - a : a;
+    long max = b < 0 ? - b : b;
+    while ( min > 0 ) {
+      int tmp = min;
+      min = max % min;
+      max = tmp;
+    }
+    return LONG2FIX(max);
+  } else {
+    /* Delegate to Integer#gcd. */
+    return rb_call_super(1, argv);
+  }
+}
+
 void
 Init_Numeric()
 {
@@ -3115,6 +3139,7 @@ Init_Numeric()
     rb_define_method(rb_cFixnum, "divmod", fix_divmod, 1);
     rb_define_method(rb_cFixnum, "quo", fix_quo, 1);
     rb_define_method(rb_cFixnum, "fdiv", fix_quo, 1);
+    rb_define_method(rb_cFixnum, "gcd", fix_gcd, -1);
     rb_define_method(rb_cFixnum, "**", fix_pow, 1);
 
     rb_define_method(rb_cFixnum, "abs", fix_abs, 0);
diff --git a/numeric.c b/numeric.c
index ec11e81..3c0c94c 100644
--- a/numeric.c
+++ b/numeric.c
@@ -3024,23 +3024,27 @@ static VALUE
 fix_gcd(int argc, VALUE *argv, VALUE self) {
   if ( argc != 1 ) {
     rb_raise(rb_eArgError, "wrong number of arguments (%d for %d)", argc, 1);
-  }
-  /* Handle Fixnum#gcd(Fixnum) here. */
-  if ( FIXNUM_P(argv[0]) ) {
-    /* fprintf(stderr, "Using Fixnum#gcd(Fixnum)\n"); */
+  } else {
+    /* Handle Fixnum#gcd(Fixnum) here. 
+     * Note: Cannot handle FIXNUM_MIN here due to overflow during negation.
+     */
     long a = FIX2LONG(self);
     long b = FIX2LONG(argv[0]);
-    long min = a < 0 ? - a : a;
-    long max = b < 0 ? - b : b;
-    while ( min > 0 ) {
-      int tmp = min;
-      min = max % min;
-      max = tmp;
-    }
-    return LONG2FIX(max);
-  } else {
-    /* Delegate to Integer#gcd. */
-    return rb_call_super(1, argv);
+
+    if ( a != FIXNUM_MIN && FIXNUM_P(argv[0]) && b != FIXNUM_MIN ) {
+      /* fprintf(stderr, "Using Fixnum#gcd(Fixnum)\n"); */
+      long min = a < 0 ? - a : a;
+      long max = b < 0 ? - b : b;
+      while ( min > 0 ) {
+       int tmp = min;
+       min = max % min;
+       max = tmp;
+      }
+      return LONG2FIX(max);
+    } else {
+      /* Delegate to Integer#gcd. */
+      return rb_call_super(1, argv);
+    }
   }
 }