I've organised recently a photography workshop in Collierville, TN (Memphis's suburbs) about the basics of digital photography. Most of the participants (around 80%) showed up with pro-consumer DSLRs but almost nobody has ever read their camera's manual. That didn't surprise me too much because who wouldn't get a headache just from looking at a manual that is a size of a big book.

But I realized only now that a camera's manual doesn't only have instructions, but it also explains you... well almost everything to get you started and to understand the basics. Let's take 'aperture' as an example. Nikon D7000's manual explains you what aperture is, how it low vs. larger apertures influence depth of field/blurring and much more. Here is a quote from the D7000's manual:

In aperture-priority auto, you choose the aperture while the camera automatically selects the shutter speed that will produce the optimal exposure. Large apertures (low f-numbers) reduce depth of field, blurring objects behind and in front of the main subject. Small apertures (high f-numbers) increase depth of field, bringing out details in the background and foreground. 

I'm fully aware that even after reading a manual, many people may still be confused; they might find a camera's manual full of gibberish and still be confused (and even angry) that the pictures they take look ugly, blurry, out of focus, etc (like the couple on the photo above).