Search Engine Optimization is a misnomer.
Everyone just wants to get to the top of Google, and to a lesser extent Bing and Yahoo, by any means possible.
It is pretty simple to do, if you follow the rules. Site structure, freshness of content and incoming links are the three legs of SEO methodology.
Here is a partial guide to How SEO Is Done.
And here's an example of success for a flameout startup client, getting to position five on Google from below 100, which generated 1000s of website visits.