diff --git a/package.json b/package.json
index 13b58eee..8f826ec0 100644
--- a/package.json
+++ b/package.json
@@ -61,6 +61,7 @@
     "rxjs": "^6.2.1"
   },
   "dependencies": {
+    "@microstates/lens": "1.0.0-beta.2",
     "funcadelic": "^0.5.0",
     "symbol-observable": "^1.2.0"
   },
diff --git a/rollup.config.js b/rollup.config.js
index 23dced82..419c63a7 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -7,7 +7,8 @@ const replace = require('rollup-plugin-replace');
 
 const external = [
   "funcadelic",
-  "symbol-observable"
+  "symbol-observable",
+  "@microstates/lens"
 ];
 
 const babelPlugin = babel({
diff --git a/src/lens.js b/src/lens.js
deleted file mode 100644
index e75e8afe..00000000
--- a/src/lens.js
+++ /dev/null
@@ -1,83 +0,0 @@
-import { Functor, map, Semigroup } from 'funcadelic';
-
-import { childAt } from './tree';
-
-class Box {
-  static get of() {
-    return (...args) => new this(...args);
-  }
-
-  static unwrap(box) {
-    return box.value;
-  }
-
-  constructor(value) {
-    this.value = value;
-  }
-}
-
-const { unwrap } = Box;
-
-class Id extends Box {}
-
-class Const extends Box {}
-
-Functor.instance(Id, {
-  map(fn, id) {
-    return Id.of(fn(id.value));
-  }
-});
-
-Functor.instance(Const, {
-  map(fn, constant) {
-    return constant;
-  }
-});
-
-export function compose(f, g) {
-  return (...x) => f(g(...x));
-}
-
-export function view(lens, context) {
-  let get = compose(unwrap, lens(Const.of));
-  return get(context);
-}
-
-export function over(lens, fn, context) {
-  let update = compose(unwrap, lens(compose(Id.of, fn)));
-  return update(context);
-}
-
-export function set(lens, value, context) {
-  return over(lens, () => value, context);
-}
-
-export function Lens(get, set) {
-  return f => context => {
-    return map(value => set(value, context), f(get(context)));
-  };
-}
-
-export const transparent = Lens(x => x, y => y);
-
-export function At(property, container) {
-  let get = context => context != null ? childAt(property, context) : undefined;
-  let set = (part, whole) => {
-    let context = whole == null ? (Array.isArray(container) ? [] : {}) : whole;
-    if (part === context[property]) {
-      return context;
-    } else if (Array.isArray(context)) {
-      let clone = context.slice();
-      clone[Number(property)] = part;
-      return clone;
-    } else {
-      return Semigroup.for(Object).append(context, {[property]: part});
-    }
-  };
-
-  return Lens(get, set);
-}
-
-export function Path(path) {
-  return path.reduce((lens, key) => compose(lens, At(key)), transparent);
-}
diff --git a/src/meta.js b/src/meta.js
index 805d0f50..87f630e9 100644
--- a/src/meta.js
+++ b/src/meta.js
@@ -1,4 +1,4 @@
-import { At, compose, transparent, over, view } from './lens';
+import { At, compose, transparent, over, view } from '@microstates/lens';
 
 export class Meta {
   static symbol = Symbol('Meta');
diff --git a/src/microstates.js b/src/microstates.js
index 92013f5c..dd2e310a 100644
--- a/src/microstates.js
+++ b/src/microstates.js
@@ -1,5 +1,5 @@
 import { append, stable, map } from 'funcadelic';
-import { set } from './lens';
+import { set } from '@microstates/lens';
 import { Meta, mount, metaOf, valueOf, sourceOf } from './meta';
 import { methodsOf } from './reflection';
 import dsl from './dsl';
diff --git a/src/pathmap.js b/src/pathmap.js
index 5941c083..dc54e98f 100644
--- a/src/pathmap.js
+++ b/src/pathmap.js
@@ -1,6 +1,6 @@
+import { view, Path } from '@microstates/lens';
 import { methodsOf } from './reflection';
 import { create } from './microstates';
-import { view, Path } from './lens';
 import { valueOf, Meta } from './meta';
 import { defineChildren } from './tree';
 import { stable } from 'funcadelic';
diff --git a/src/storage.js b/src/storage.js
index 980b152f..19b8b406 100644
--- a/src/storage.js
+++ b/src/storage.js
@@ -1,4 +1,4 @@
-import { view, set, Path } from './lens';
+import { view, set, Path } from '@microstates/lens';
 
 export default class Storage {
   constructor(value, observe = x => x) {
diff --git a/src/tree.js b/src/tree.js
index 7b630cff..e3126fa9 100644
--- a/src/tree.js
+++ b/src/tree.js
@@ -5,14 +5,6 @@ import CachedProperty from './cached-property';
 export const Tree = type(class {
   static name = 'Tree';
 
-  childAt(key, parent) {
-    if (parent[Tree.symbol]) {
-      return this(parent).childAt(key, parent);
-    } else {
-      return parent[key];
-    }
-  }
-
   defineChildren(fn, parent) {
     if (parent[Tree.symbol]) {
       return this(parent).defineChildren(fn, parent);
@@ -24,4 +16,4 @@ export const Tree = type(class {
   }
 });
 
-export const { childAt, defineChildren } = Tree.prototype;
+export const { defineChildren } = Tree.prototype;
diff --git a/src/types/array.js b/src/types/array.js
index f31fbfb9..ad368d05 100644
--- a/src/types/array.js
+++ b/src/types/array.js
@@ -1,8 +1,8 @@
-import { At, set } from '../lens';
+import { at, At, set, Context } from '@microstates/lens';
 import { mount, valueOf } from '../meta';
 import { create } from '../microstates';
 import parameterized from '../parameterized';
-import { Tree, childAt } from '../tree';
+import { Tree } from '../tree';
 
 export default parameterized(T => class ArrayType {
   static T = T;
@@ -88,7 +88,7 @@ export default parameterized(T => class ArrayType {
           get done() { return next.done; },
           get value() {
             if (!next.done) {
-              return childAt(index, array);
+              return at(index, array);
             } else {
               return undefined;
             }
@@ -100,16 +100,18 @@ export default parameterized(T => class ArrayType {
 
   static initialize() {
 
-    Tree.instance(this, {
-      childAt(key, array) {
+    Context.instance(this, {
+      at(key, array) {
         if (typeof key === 'number') {
           let value = valueOf(array)[key];
           return mount(array, create(T, value), key);
         } else {
           return array[key];
         }
-      },
+      }
+    });
 
+    Tree.instance(this, {
       defineChildren(fn, array) {
         let generate = array[Symbol.iterator];
         return Object.defineProperty(array, Symbol.iterator, {
diff --git a/src/types/object.js b/src/types/object.js
index f7518c00..9e2df766 100644
--- a/src/types/object.js
+++ b/src/types/object.js
@@ -1,10 +1,10 @@
 import { append, filter, map } from 'funcadelic';
+import { at, Context } from '@microstates/lens';
 import { reduce, query } from '../query';
 import parameterized from '../parameterized';
 import { valueOf, mount } from '../meta';
 import { create } from '../microstates';
-import { Tree, childAt } from '../tree';
-
+import { Tree } from '../tree';
 
 export default parameterized(T => class ObjectType {
   static T = T;
@@ -59,7 +59,7 @@ export default parameterized(T => class ObjectType {
           get done() { return next.done; },
           get value() {
             if (!next.done) {
-              return new Entry(next.value, childAt(next.value, object));
+              return new Entry(next.value, at(next.value, object));
             } else {
               return undefined;
             }
@@ -70,15 +70,19 @@ export default parameterized(T => class ObjectType {
   }
 
   static initialize() {
-    Tree.instance(this, {
-      childAt(key, object) {
+
+    Context.instance(this, {
+      at(key, object) {
         if (typeof key !== 'string') {
           return object[key];
         } else {
           let value = valueOf(object)[key];
           return mount(object, create(T, value), key);
         }
-      },
+      }
+    });
+
+    Tree.instance(this, {
       defineChildren(fn, object) {
         let generate = object[Symbol.iterator];
         return Object.defineProperty(object, Symbol.iterator, {
diff --git a/tests/lens.test.js b/tests/lens.test.js
deleted file mode 100644
index eddfee2a..00000000
--- a/tests/lens.test.js
+++ /dev/null
@@ -1,25 +0,0 @@
-/* global describe, it, beforeEach */
-import expect from 'expect';
-import { compose, view, set, At } from '../src/lens';
-
-describe('At', function() {
-  let lens;
-  beforeEach(function() {
-    lens = compose(At(0, []), At("hello"));
-  });
-
-  it('instantiates objects of the correct type at each path', function() {
-    expect(set(lens, "world", undefined)).toEqual([{hello: 'world'}]);
-  });
-
-  it('set-get: view retrievs what set put in', function() {
-    let cookie = {};
-    let object = set(lens, cookie, undefined);
-    expect(view(lens, object)).toBe(cookie);
-  });
-
-  it('get-set: If you set focus to the same value it has, the whole does not change', function() {
-    let object = set(lens, "world", undefined);
-    expect(set(lens, "world", object)).toBe(object);
-  });
-});
diff --git a/yarn.lock b/yarn.lock
index 23d552be..f0896c14 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -662,6 +662,13 @@
     "@types/istanbul-lib-coverage" "^1.1.0"
     "@types/yargs" "^12.0.9"
 
+"@microstates/lens@1.0.0-beta.2":
+  version "1.0.0-beta.2"
+  resolved "https://registry.yarnpkg.com/@microstates/lens/-/lens-1.0.0-beta.2.tgz#b43badbe038a90f95f13f4ae57a34fddd380c356"
+  integrity sha512-WrPBgPut3h8c7/Yl1tIaA8Fw4TV80mx3EXJGvumBhx15GE+z31HB+31loz9+I4dbGq6xC4Xi7rhMXdiBqRK6Ug==
+  dependencies:
+    funcadelic "^0.5.7"
+
 "@types/estree@0.0.39":
   version "0.0.39"
   resolved "https://registry.yarnpkg.com/@types/estree/-/estree-0.0.39.tgz#e177e699ee1b8c22d23174caaa7422644389509f"
@@ -1814,7 +1821,7 @@ fs.realpath@^1.0.0:
   resolved "https://registry.yarnpkg.com/fs.realpath/-/fs.realpath-1.0.0.tgz#1504ad2523158caa40db4a2787cb01411994ea4f"
   integrity sha1-FQStJSMVjKpA20onh8sBQRmU6k8=
 
-funcadelic@^0.5.0:
+funcadelic@^0.5.0, funcadelic@^0.5.7:
   version "0.5.7"
   resolved "https://registry.yarnpkg.com/funcadelic/-/funcadelic-0.5.7.tgz#e76f6a9028985531924c1159dc1c930f5b00acb2"
   integrity sha512-kwKSJVAd2FNFmBgku81FC6VJCQdgcT/gtwG9z7H7FxL4NlDKsbdGqLwtjbDlYgR77t+NuT8phBLkmLSKsg1J5w==