Three dimensional graphics hardware is fast becoming, not merely a staple of computer systems, but an indispensable component. Many operating systems directly use and even require some degree of 3D rendering hardware. Even in the increasingly important mobile computing space, 3D graphics hardware is a standard feature of all but the lowest power devices. Understanding how to make the most of that hardware is a difficult challenge, particularly for someone new to graphics and rendering.
An online readable book Learning Modern 3D Graphics Programming by Jason L. McKesson is intended to teach you how to be a graphics programmer. It is not aimed at any particular graphics field; it is designed to cover most of the basics of 3D rendering. So if you want to be a game developer, a CAD program designer, do some computer visualization, or any number of things, this book can still be an asset for you.