Reddit reviews Search Engine Marketing, Inc.: Driving Search Traffic to Your Company's Web Site (IBM Press)

in all honesty, this industry is so fast-paced and evolving so quickly that i don't think a book is going to give you the best information. in my opinion, the best thing to do is subscribe your RSS reader to SEOMoz, Youmoz, Search Engine Journal, Search Engine Land, Search Engine Watch, Distilled.net, Bruce Clay, SEO by the Sea, and, of course, Google and Bing. there are other ones you'll definitely want to take a look at (for my interests, i'm also subscribed to Copyblogger, Smashing Magazine, and ReelSEO). reading those and staying up to date with them will make sure that you keep up with the latest algo changes, experiments, and ideas.

all that being said, i did start learning SEO from a book. it was this one. it's from 2008, so it's already outdated, but since i didn't have a marketing background, it gave me a good entrance into it. i learned some fundamentals from the book, which was good, but any of the details are either wrong or outdated, so if you do read it, take it with several pinches of salt. i've also heard good things about the SEO for Dummies books, with bruce clay. he's rather well-renowned in the industry, so there's bound to be some good, actionable stuff in there. i haven't read it myself, so i can't say for sure.

at the end of the day, any agency or company looking for an SEO person wants to see results, so once you get all this stuff in your head, play with it on your own websites (i recommend having multiples, and NEVER run dangerous experiments on your money sites!) to see what works. one of the best things about this industry is that there is no certain 1 way to rank well (whatever G may say), so it rewards people who are curious and are willing to try something crazy to rank.

good luck, and have fun! ask more questions here if you have them; this seems to be a fairly active subreddit for having such a small readership.