diff --git a/README.md b/README.md
index 8ca0dbc..7e6c594 100644
--- a/README.md
+++ b/README.md
@@ -35,16 +35,17 @@ import SizeMe from 'react-sizeme';
 
 class MyComponent extends Component {
   render() {
-    // Receive width and height via "size" prop!
-    const { width, height } = this.props.size;
+    // We receive width and height via "size" prop!
+    const { width } = this.props.size;
   
     return (
-      <div>My dimensions are {width}px by {height}px</div>
+      <div>My width is {width}px</div>
     );
   }
 }
 
-export default SizeMe()(MyComponent);  // Wired up here!
+// Wired up here!
+export default SizeMe()(MyComponent);
 ```
 
 ## Usage and API Details
@@ -65,19 +66,32 @@ You first have to pass the `SizeMe` function a configuration object.  The entire
 
 ```javascript
 const SizeMeHOC = SizeMe({
-  // If true any changes to `width` will result in a new `size` prop being
-  // passed to your Component.
+  // If true, then any changes to your Components rendered width will cause an 
+  // recalculation of the "size" prop which will then be be passed into 
+  // your Component.
+  // If false, then any changes to your Components rendered width will NOT 
+  // cause any recalculation of the "size" prop. Additionally any "size" prop 
+  // that is passed into your Component will always have a `null` value 
+  // for the "width" property.
   monitorWidth: true, 
-  // If true any changes to `height` will result in a new `size` prop being
-  // passed to your Component. 
+  // If true, then any changes to your Components rendered height will cause an 
+  // recalculation of the "size" prop which will then be be passed into 
+  // your Component.
+  // If false, then any changes to your Components rendered height will NOT 
+  // cause any recalculation of the "size" prop. Additionally any "size" prop 
+  // that is passed into your Component will always have a `null` value 
+  // for the "height" property.
   monitorHeight: false,
-  // The maximum speed, in milliseconds, at which size changes should be 
-  // propogated to your Components. This should not be set to lower than 16.
+  // The maximum frequency, in milliseconds, at which size changes should be 
+  // recalculated when changes in your Component's rendered size are being
+  // detected. This should not be set to lower than 16.
   refreshRate: 16
 });
 ```
 
-__IMPORTANT__: We don't monitor height by default, so if you use the default settings and your component only changes in height it won't recieve an updated `size` prop.  I figured that in most cases we care about the width only and it would be annoying if vertical text spanning kept throwing out updates.
+__IMPORTANT__: We don't monitor height by default, so if you use the default settings and your component only changes in height it won't cause a recalculation of the `size` prop.  I figured that in most cases we care about the width only and it would be annoying if vertical text spanning kept throwing out updates.
+
+__IMPORTANT__: If you aren't monitoring a specific dimension (width or height) you will be provided `null` values for the respective dimension.  This is to avoid any possible misconfigured implementation whoopsies.
 
 __IMPORTANT__: `refreshRate` is set very low.  If you are using this library in a manner where you expect loads of active changes to your components dimensions you may need to tweak this value to avoid browser spamming. 
 
diff --git a/src/SizeMe.js b/src/SizeMe.js
index 14327d1..6d69e2a 100644
--- a/src/SizeMe.js
+++ b/src/SizeMe.js
@@ -172,7 +172,10 @@ function SizeMe(config = defaultConfig) {
 
       checkIfSizeChanged = throttle((el) => {
         const { width, height } = el.getBoundingClientRect();
-        const next = { width, height };
+        const next = {
+          width: monitorWidth ? width : null,
+          height: monitorHeight ? height : null
+        };
 
         if (this.hasSizeChanged(this.state, next)) {
           this.setState(next);
diff --git a/test/SizeMe.test.js b/test/SizeMe.test.js
index b393e87..659c869 100644
--- a/test/SizeMe.test.js
+++ b/test/SizeMe.test.js
@@ -66,9 +66,7 @@ describeWithDOM(`Given the SizeMe library`, () => {
   describe(`And the resize detector`, () => {
     describe(`When mounting and unmounting the placeholder component`, () => {
       it(`Then the resizeDetector registration and deregistration should be called`, () => {
-        const SizeAwareComponent = SizeMe()(
-          ({ size: { width, height } }) => <div>{width} x {height}</div>
-        );
+        const SizeAwareComponent = SizeMe()(() => <div></div>);
 
         const mounted = mount(<SizeAwareComponent />);
 
@@ -84,7 +82,7 @@ describeWithDOM(`Given the SizeMe library`, () => {
 
     describe(`When mounting and unmounting a size aware component`, () => {
       it(`Then the resizeDetector registration and deregistration should be called`, () => {
-        const SizeAwareComponent = SizeMe()(
+        const SizeAwareComponent = SizeMe({ monitorHeight: true })(
           ({ size: { width, height } }) => <div>{width} x {height}</div>
         );
 
@@ -123,9 +121,7 @@ describeWithDOM(`Given the SizeMe library`, () => {
   describe(`When rendering a size aware component`, () => {
     describe(`And no className or style has been provided`, () => {
       it(`Then it should render the default placeholder`, () => {
-        const SizeAwareComponent = SizeMe()(
-          ({ size: { width, height } }) => <div>{width} x {height}</div>
-        );
+        const SizeAwareComponent = SizeMe()(() => <div></div>);
 
         const mounted = mount(<SizeAwareComponent />);
 
@@ -136,9 +132,7 @@ describeWithDOM(`Given the SizeMe library`, () => {
 
     describe(`And only a className has been provided`, () => {
       it(`Then it should render a placeholder with the className`, () => {
-        const SizeAwareComponent = SizeMe()(
-          ({ size: { width, height } }) => <div>{width} x {height}</div>
-        );
+        const SizeAwareComponent = SizeMe()(() => <div></div>);
 
         const mounted = mount(<SizeAwareComponent className={`foo`} />);
 
@@ -149,9 +143,7 @@ describeWithDOM(`Given the SizeMe library`, () => {
 
     describe(`And only a style has been provided`, () => {
       it(`Then it should render a placeholder with the style`, () => {
-        const SizeAwareComponent = SizeMe()(
-          ({ size: { width, height } }) => <div>{width} x {height}</div>
-        );
+        const SizeAwareComponent = SizeMe()(() => <div></div>);
 
         const mounted = mount(<SizeAwareComponent style={{ height: `20px` }} />);
 
@@ -162,9 +154,7 @@ describeWithDOM(`Given the SizeMe library`, () => {
 
     describe(`And a className and style have been provided`, () => {
       it(`Then it should render a placeholder with both`, () => {
-        const SizeAwareComponent = SizeMe()(
-          ({ size: { width, height } }) => <div>{width} x {height}</div>
-        );
+        const SizeAwareComponent = SizeMe()(() => <div></div>);
 
         const mounted = mount(
           <SizeAwareComponent style={{ height: `20px` }} className={`foo`} />
@@ -175,11 +165,53 @@ describeWithDOM(`Given the SizeMe library`, () => {
       });
     });
 
-    describe(`And the size event has occurred`, () => {
-      it(`Then the actual size aware component should render`, () => {
-        const refreshRate = 30;
+    describe(`And the size event has occurred when only width is being monitored`, () => {
+      it(`Then expected sizes should be provided to the rendered component`, () => {
+        const SizeAwareComponent = SizeMe({ monitorWidth: true, monitorHeight: false })(
+          ({ size: { width, height } }) => <div>{width} x {height || `null`}</div>
+        );
+
+        const mounted = mount(<SizeAwareComponent />);
+
+        // Initial render should be as expected.
+        expect(mounted.html()).to.equal(placeholderHtml);
+
+        // Get the callback for size changes.
+        const checkIfSizeChangedCallback = resizeDetectorMock.listenTo.args[0][1];
+        checkIfSizeChangedCallback({
+          getBoundingClientRect: () => ({ width: 100, height: 150 })
+        });
+
+        // Update should have occurred immediately.
+        expect(mounted.text()).to.equal(`100 x null`);
+      });
+    });
+
+    describe(`And the size event has occurred when only height is being monitored`, () => {
+      it(`Then expected sizes should be provided to the rendered component`, () => {
+        const SizeAwareComponent = SizeMe({ monitorWidth: false, monitorHeight: true })(
+          ({ size: { width, height } }) => <div>{width || `null`} x {height}</div>
+        );
+
+        const mounted = mount(<SizeAwareComponent />);
+
+        // Initial render should be as expected.
+        expect(mounted.html()).to.equal(placeholderHtml);
+
+        // Get the callback for size changes.
+        const checkIfSizeChangedCallback = resizeDetectorMock.listenTo.args[0][1];
+        checkIfSizeChangedCallback({
+          getBoundingClientRect: () => ({ width: 100, height: 150 })
+        });
 
-        const SizeAwareComponent = SizeMe({ refreshRate })(
+        // Update should have occurred immediately.
+        expect(mounted.text()).to.equal(`null x 150`);
+      });
+    });
+
+    describe(`And the size event has occurred when width and height are being monitored`, () => {
+      it(`Then expected sizes should be provided to the rendered component`, () => {
+        const SizeAwareComponent = SizeMe({ monitorWidth: true, monitorHeight: true })(
           ({ size: { width, height } }) => <div>{width} x {height}</div>
         );
 
@@ -191,19 +223,17 @@ describeWithDOM(`Given the SizeMe library`, () => {
         // Get the callback for size changes.
         const checkIfSizeChangedCallback = resizeDetectorMock.listenTo.args[0][1];
         checkIfSizeChangedCallback({
-          getBoundingClientRect: () => ({ width: 100, height: 100 })
+          getBoundingClientRect: () => ({ width: 100, height: 150 })
         });
 
         // Update should have occurred immediately.
-        expect(mounted.text()).to.equal(`100 x 100`);
+        expect(mounted.text()).to.equal(`100 x 150`);
       });
     });
 
     describe(`And it receives new non-size props`, () => {
       it(`Then the new props should be passed into the component`, () => {
-        const refreshRate = 16;
-
-        const SizeAwareComponent = SizeMe({ refreshRate })(
+        const SizeAwareComponent = SizeMe({ monitorHeight: true, monitorWidth: true })(
           function ({ size: { width, height }, otherProp }) {
             return <div>{width} x {height} & {otherProp}</div>;
           }