If you are entirely new to Mac OS X you should get a 'missing manual' type book. I recommend the David Pogue books, especially. He (and I suppose his editing staff) have been churning out huge tomes on each of the Mac OS iterations. They are very well written, very clear and informal in tone. A computing system like OS X has hundreds of thousands, perhaps millions, of capabilities, and an enormous number of command possibilities, most of them hidden (even in the Apple online Help). To maximize the power of your computer, and your fun, get a good manual (manuals).
**Life is short; judgment is difficult**