You can use the opposition in several ways. Basically the opposition is a specific and recurrent form of Zugzwang. Often the opposition doesn't just mean the basic "Kings 1 square apart" pattern. If there are no pawn moves in a King and Pawn endgame and a King is forced to retreat, it is probably a form of Opposition.
What does it mean, really, to have the "opposition?"

I can explain it but reference source material below explains it well.
In a nut shell if you gain opposition with your king against the opponent king on the same file, and he then has to make a move next, then you have the advantage to move your pawn or gain a piece.
The side, white or black that looses opposition often losses the game, depends on the pieces left on the board.
http://en.wikivisual.com/index.php/Endgame
go to page 3 from the top.
If you have explorer browser you can go to the top bar on the internet page and select edit on the left just after file. Click or select the item that says find on this page, a box will show up, type in the box the word "opposition" and press the "nexty" button, this will bring to where on the page the word "oppositon" is in the text, read and press again "next", do it until it brings you back to the first sentence you have read.
I also have the book and went thru twice already, well since 1year and 4 months.
Best to you.
Paul211,
Thank you. I found the pages and printed them out. It seems to explain it better (at least to me) than Silman does.
I am wondering if problem #1 in the new Computer Workout section on this site, (under Learn) illustrates the way opposition works. Problem is called "a common Zugzwang"
Thanks to all for your help.
stwils
I am dipping into Silman's Reassess Your Chess. (Only the first 52 pages as that what he recommends for non advanced players.)
Right off he talks about who has the "opposition."
I know that kings can not get near each other. I understand that. But what does he really mean by the word "opposition?" Does he mean advantage? Or the disadvantage?
I like his writing style. But I can't seem to get beyond the word opposition and what that means on the chessboard. (or to me.)
It seems that in some sitiuations with kings it is NOT to your advantage to have it be your move as that somehow puts you into opposition.
Would someone please explain this in just plain language to me?
stwils