1/ Your monitor works with light, so every colour it can display is buit up out of the three components Red, Green and Blue. More intensity in either means more light. Everything includes, indeed, the WWW.
2/ Everything that is printed needs ink. The basic ink colours are Cyan blue, Magenta red and Yellow. Black is added because these three together fon't go any deeper than a deep muddy brown.
3/ To reproduce full colour photography etc, these four colour inks are used. Sometimes, because many colours cannot be made by mixing Cmy and k, printers add more colours like, for example a lighter cyan and a lighter magenta so that the full range can expand. This can be as well on big offset presses as on a photo deskjet printer.
4/ On an offset press, one can put any ink one likes, even varnish and metallic inks. This way, even more colours can be printed. Mostly these are used for text or fills in fancy colours. To reduce the vast amopunt of inks a printer should need, and to give a standard set one can rely on, most of these inks are mixed from a basic set.
One of these set is the pantone set. You look in the book, choose your colour and then the printer can mix it, starting from his basic inks.
5/ You can never exactly see on a monitor what you will get when it's printed. Many, very expensive proof print systems can be used for that, like, for example Chromalin.
6/ What's more, every paper is different. And the pressure on the rolls of the offset press, and the humidity, and the number of prints that has already been made with the rubber blanket etc, all these influence the result. Calibrating an offset press is as good as impossible.
7/ Calibrating your home printer is also quite difficult. And I personally have come to the shocking conclusion that the Adobe Gamma Utility is not capable of calibrating my monitor in such a way that I get a reliable image that resembles as close as possible my print-output. I am preparing a text on that, but it takes time as, in the first place, I'm an artist, not a teacher. Basically it is this: print some reliable patches like black, white and greys, and scan these. They are what your printer considers to be black, white and grey. The scan will tell you how your scanner sees them, and then photoshop can adjsut them even better with levels/curves. You can save this setting. And then, when you reprint it and the result is as good as identical, only then you attack your monitor. It is only a viewing device, and it has no influence on what is calculated inside your puter. This is not the way the "specialists" say it must be done, but it is the only way that is logical and that really works.
Speaking of teaching...really, believe me: when you want to dive into design and DTP, it's best to follow some kind of course on it. The matter is too complex and there's too much to be said and done to explain on a site like this. Don't forget that there are books of hundreds of pages on the subject, and also that many "experts" constantly disagree with one-another...
cheers, E.
A slight deviation.... 
Linear Mode
