You need to learn the fundamentals. Read the first link in my signature, then go to websitepublisher.net/seo-guide for more information.
You may get the SEO book, it costs $79 but it has a 90 day money back garantee. By the way, look at my signature
and do not forget to practice everything you have read. Theory is good, but without practical support it is nothing
Read this forum and use google for anything you don't quite understand. No need to throw money at books and guides. the information is out there and it's all free. You just need to look
Two rules of thumb. When it comes to SEO, if you have to pay money to "learn" something, stay away from it. There's so much information out there that you shouldn't have any trouble finding what you are looking for and have it be correct and accurate as of the time it was published. The link in my signature and the link to Chris Beasley's Web site (as well as the Search Engine Optimization FAQ on SitePoint's forums) are great places to start. Second, I've said it before, and others have said it elsewhere (though why the book enjoys a cult-like following here, I'll never know), don't buy the SEO Book. It is inaccurate, misleading and filled with lots of useless information (like how .edu backlinks are allegedly "worth more" despite the search engines themselves stating they're not). Seriously, why SPEND MONEY on something you can get for free (by the way, Chris has a .pdf version of his SEO guide available for download - all you have to do is register on his forums to get it)?
how about the site you are currently on?. there is a ton of infor available for free. you shouldn't have to pay for anything
A lot of the information here is of dubious value. Not all of it, and there are some real gems, but finding it among the clutter can prove to be a pain in the neck at times. The same is true of any forum though - even SitePoint (though they do a great job of filtering out the junk without actually removing posts).
There are lots of site, who are providing good SEO information. You can check this >> www.seobook.com
I think the best site to study SEO is DP itself.Most of the people comes here with little knowledge and build up.
Indeed you could try the seobook as well. Other sources you could look at is the forum here, it is full of tips and tricks you can learn, if you care take a look at the seo resources in my first signature link.
read this forum and read articles on seochat.com , read google webmaster guidelines and if you like you can follow links in my signature.
The problem I have with books on topics like SEO is that SEO is always changing. What works today might get you penalized tomorrow. The pages in that book will never change with the times, quality forums like this one and the established websites will.