Peter Kent's book in the For Dummies series offers a useful introduction to search engine optimization. He does not promise miracles, but focuses on specific measures to increase the ranking of your site.

Peter Kent: Search Engine Optimization for Dummies. Hoboken, NJ: Wiley Publishing, 2004.
ISBN: 0-7645-6758-6
Search engine optimization, or SEO, is a field overshadowed by sensational claims and sometimes dubious practices. If your business has a website, you naturally want it to obtain high rankings in the major search engines so that potential customers can find you. Yet you might be suspicious of companies that promise to catapult your website to #1 ranking in almost no time ot announce that they will submit your site to thousands of search engines and web directories.
Peter Kent's book in the For Dummies series offers a useful introduction to search engine optimization. He starts out by surveying the various search sites and search systems and explains who gets results from whom. He then suggests how yo give your website a quick makeover to give it greater visibility.
Throughout the book, Kent repeatedly emphasiszes functionality over slick web technologies that might actually hinder search engines in finding your site. His second emphasis is on content as a lure for search engines.
Kent uses a fictitious website on "rodent racing" to give the reader very specific advice on picking the right keywords, getting into search engines, optimizing code, finding specialized directories, and much more. With over 350 pages (and a detailed index), this book offers you a wealth of suggestions and useful advice, whether you want to improve your website's ranking by yourself or hire a SEO firm to do it.
As an added bonus, the publisher offers a website which contains all the links mentioned in the book (ordered by chapter), which comes in handy when you try to follow the author's suggestions.

ABOUT THE AUTHOR
Pamela Bruce lives in Austin, TX. She is the owner of Love Beads Unlimited and sells the sterling silver and Swarovski crystal bead jewelry she designs and creates both in her eBay store (http://stores.ebay.com/LOVE-BEADS-UNLIMITED) and on her website at http://www.lovebeadsunlimited.com, where you can also download the free e-book "A Consumer's Guide to Buying Bead Jewelry Online".