diff --git a/AUTHORS b/AUTHORS
index 93fedd2..7ba5488 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -1 +1,10 @@
-Paul R. Tagliamonte <tag@pault.ag>
+Code contributors:
+
+ - Paul R. Tagliamonte <tag@pault.ag>
+
+I'd also like to thank the following people:
+
+ - Kragen Sitaker:
+    Major thanks goes to Kragen on helping me work through some of the
+    namespacing crap. I think the majority of the approach taken now
+    with expressions' eval bits is his doing in one way or another.
diff --git a/bin/hython b/bin/hython
new file mode 100755
index 0000000..3444340
--- /dev/null
+++ b/bin/hython
@@ -0,0 +1,6 @@
+#!/usr/bin/env python
+
+from hy.lang.importer import _hy_import_file
+import sys
+
+mod = _hy_import_file(sys.argv[1], '<stdin>')
diff --git a/hy/compiler/modfaker.py b/hy/compiler/modfaker.py
index ba4ce52..74e7fb6 100644
--- a/hy/compiler/modfaker.py
+++ b/hy/compiler/modfaker.py
@@ -120,7 +120,7 @@ def forge_module(name, fpath, forest):
     def shim():
         ns = globals()
         for tree in _hy_forest:
-            tree.set_namespace(ns, {})
+            tree.set_namespace(ns)
 
         for tree in _hy_forest:
             tree()
diff --git a/hy/lang/bool.py b/hy/lang/bool.py
index de080c4..78a37ee 100644
--- a/hy/lang/bool.py
+++ b/hy/lang/bool.py
@@ -5,5 +5,5 @@ class HYBool(HYObject):
     def __init__(self, val):
         self._val = val
 
-    def eval(self, *args, **kwargs):
+    def eval(self, lns, *args, **kwargs):
         return self._val == True
diff --git a/hy/lang/builtins.py b/hy/lang/builtins.py
index 218797b..8ddf1b2 100644
--- a/hy/lang/builtins.py
+++ b/hy/lang/builtins.py
@@ -1,37 +1,40 @@
 #
 import sys
+from hy.lang.internals import HYNamespaceCOW
 
 
-def _define(obj):
+def _define(obj, lns):
     fd = obj.get_invocation()
     args = fd['args']
     obj.namespace[args[0]] = args[1]()
 
 
-def _fn(obj):
+def _fn(obj, lns):
     fd = obj.get_invocation()
     args = fd['args']
     sig = args[0]
     meth = args[1]
 
     def _(*args, **kwargs):
+        l = lns.clone()
+        m = meth.copy()
         for i in range(0, len(sig)):
             name = sig[i]
             value = args[i]
-            meth.local_namespace[name] = value
+            l[name] = value
 
-        ret = meth(*args, **kwargs)
+        ret = m.eval(l, *args, **kwargs)
         return ret
     return _
 
 
-def _kwapply(obj):
+def _kwapply(obj, lns):
     fd = obj.get_invocation()
     subshell, kwargs = fd['args']
-    return subshell.eval(**kwargs)
+    return subshell.eval(lns.clone(), **kwargs)
 
 
-def _import(obj):
+def _import(obj, lns):
     ns = obj.namespace
     fd = obj.get_invocation()
     args = fd['args']
@@ -44,13 +47,13 @@ def _import(obj):
         ns[basename] = mod
 
 
-def _if(obj):
+def _if(obj, lns):
     fd = obj.get_invocation()
     args = fd['args']
-    if args[0].eval():
-        return args[1].eval()
+    if args[0].eval(lns.clone()):
+        return args[1].eval(lns.clone())
     else:
-        return args[2].eval()
+        return args[2].eval(lns.clone())
 
 
 builtins = {
diff --git a/hy/lang/expression.py b/hy/lang/expression.py
index 65eba36..6a63981 100644
--- a/hy/lang/expression.py
+++ b/hy/lang/expression.py
@@ -2,7 +2,7 @@ from hy.lang.hyobj import HYObject
 from hy.lang.builtins import builtins
 
 
-class HYExpression(list, HYObject):
+class HYExpression(HYObject, list):
     def __init__(self, nodes):
         self += nodes
 
@@ -24,17 +24,17 @@ class HYExpression(list, HYObject):
     def peek(self):
         return self.get_invocation()['function']
 
-    def eval(self, *args, **kwargs):
+    def eval(self, lns, *args, **kwargs):
         fn = self.peek()
 
         if fn in builtins:
             # special-case builtin handling.
-            return builtins[fn](self)
+            return builtins[fn](self, lns)
 
         things = []
         for child in self.get_children():
             c = child.copy()
-            things.append(c())
+            things.append(c.eval(lns.clone()))
 
-        ret = self.lookup(fn)(*things, **kwargs)
+        ret = self.lookup(lns, fn)(*things, **kwargs)
         return ret
diff --git a/hy/lang/hyobj.py b/hy/lang/hyobj.py
index a04d216..0ed1327 100644
--- a/hy/lang/hyobj.py
+++ b/hy/lang/hyobj.py
@@ -1,44 +1,38 @@
 from hy.lang.internals import HYNamespaceCOW
 
 class HYObject(object):
-    def set_namespace(self, ns, ls):
+    def set_namespace(self, ns):
         self.namespace = ns
-        nns = HYNamespaceCOW(ls)
-        self.local_namespace = nns
-
         for c in self.get_children():
-            c.set_namespace(ns, nns)
+            c.set_namespace(ns)
 
     def get_children(self):
         return []
 
     def __call__(self, *args, **kwargs):
-        return self.eval(*args, **kwargs)
+        ns = HYNamespaceCOW({})  # Each invocation needs it's own ns
+        return self.eval(ns, *args, **kwargs)
 
-    def lookup(self, fn):
-        callee = None
-        if fn in self.local_namespace:
-            callee = self.local_namespace[fn]
+    def lookup(self, lns, fn):
+        if fn in lns:
+            return lns[fn]
 
-        elif callee is None and fn in self.namespace:
-            callee = self.namespace[fn]
+        if fn in self.namespace:
+            return self.namespace[fn]
 
-        elif callee is None and "." in fn:
+        if "." in fn:
             lon, short = fn.rsplit(".", 1)
-            holder = self.lookup(lon)
-            callee = getattr(holder, short)
-
-        if callee is not None:
-            return callee
+            holder = self.lookup(lns, lon)
+            return getattr(holder, short)
 
         raise Exception("No such symbol: `%s`" % (fn))
 
-    def eval(self, *args, **kwargs):
+    def eval(self, lns, *args, **kwargs):
         for node in self.get_children():
-            node.eval(*args, **kwargs)
+            node.eval(lns, *args, **kwargs)
         return self
 
     def copy(self):
         new = type(self)(self)
-        new.set_namespace(self.namespace, self.local_namespace)
+        new.set_namespace(self.namespace)
         return new
diff --git a/hy/lang/internals.py b/hy/lang/internals.py
index 4a29178..289fa43 100644
--- a/hy/lang/internals.py
+++ b/hy/lang/internals.py
@@ -18,3 +18,6 @@ class HYNamespaceCOW(object):
 
     def __setitem__(self, key, value):
         self._mute[key] = value
+
+    def clone(self):
+        return HYNamespaceCOW(self)
diff --git a/hy/lang/list.py b/hy/lang/list.py
index 90775ed..264ab3f 100644
--- a/hy/lang/list.py
+++ b/hy/lang/list.py
@@ -1,7 +1,7 @@
 from hy.lang.hyobj import HYObject
 
 
-class HYList(list, HYObject):
+class HYList(HYObject, list):
     def __init__(self, nodes):
         self += nodes
 
diff --git a/hy/lang/number.py b/hy/lang/number.py
index e852d71..348e094 100644
--- a/hy/lang/number.py
+++ b/hy/lang/number.py
@@ -3,10 +3,8 @@ from hy.lang.hyobj import HYObject
 
 class HYNumber(HYObject, int):
     def __new__(cls, number, *args, **kwargs):
-        if isinstance(number, HYObject):
-            number = number.eval()
         number = int(number)
         return super(HYNumber, cls).__new__(cls, number)
 
-    def eval(self, *args, **kwargs):
+    def eval(self, lns, *args, **kwargs):
         return int(self)
diff --git a/hy/lang/symbol.py b/hy/lang/symbol.py
index 729d129..dca8919 100644
--- a/hy/lang/symbol.py
+++ b/hy/lang/symbol.py
@@ -5,6 +5,6 @@ class HYSymbol(HYString):
     def __init__(self, string):
         self += string
 
-    def eval(self, *args, **kwargs):
-        obj = self.lookup(self)
+    def eval(self, lns, *args, **kwargs):
+        obj = self.lookup(lns, self)
         return obj