I have lost my address window at the top of the screen on my MacBook?

Look to see if your web browser page in in the corner of your dock. It should be to the left of the trash can.

If not there, go onto your hard drive icon, open the applications folder, and click on the safari or firefox icon (if you’re using that) or click on the compass or fox icons on your dock.

If Firefox
View—> Toolbars—> Navigation Toolbar

Safari
View—> Show Toolbars

@johnpowell Thank you, sir! You are as fantastic as I have heard!!!

@johnpowell covered most of it, but you can also use keyboard shortcut Cmd+L to go directly to the location field. This even works if it’s hidden, it will show the location bar and when you are done using it it will disappair again. This gives you the opportunity to get 24 more pixels of browsing space!