I was working within my Indesign document and must have accidentally hit a key that turned the background of my document black while also hiding all of my guides and text/images boxes. Any suggestions? Thanks!! 
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3Possible duplicate of Why did my InDesign preview mode background turn black? – Scott Nov 25 '18 at 5:17
What you see in black is not your document, but a virtual container around your document. Kind of like the table your book sits on top of.
Accidentally you may have hit W which activates this 'Preview' mode. In which case just hit W again and you're back to the initial situation.
Another likely shortcut you may have hit is Shift+W which does the same but in full screen mode.
