My instructor told me to read up about slow flight and steep turns before my next lesson. They are not in my textbook that I bought but he said they were in a book on the FAA website. Does anyone know which one it is?

He's probably talking about the Pilot's Handbook of Aeronautical Knowledge "PHAK" and/or the Pilot's Flying Handbook. Both are free FAA authored pdf-books available on their website. Having real paper copies of both is also good idea.

More than likely he is talking about the Airplane Flying Handbook ( FAA-H-8083-3A ). A must have for learning any maneuver throughout your training.

Great info from everyone else so far. Be extremely wary of "course textbooks", as they tend to suck you in and make you ignore all the resources that are used to compile the information in the first place. The Practical Test Standards (another publication you should be very familiar with) has a list of all the valid references for a checkride, and any of the resources there are public domain, such as the handbooks mentioned earlier, advisory circulars, regulations, etc., so there's little need to "buy" anything, although printing some of them out is recommended. I've never much cared for the Jepp type pre-packaged courses that try to teach you completely out of one book. I've seen more than one person get totally tripped up on a checkride because they never actually had to look up the information for "real" and use the actual resource. Good luck though, it looks like you are being pointed in the right direction.

^^THIS

I can't even begin to count the number of people that I failed on phase checks because they didn't know what the FARs were and couldn't look up even the most basic of information.

The FAA books contain all the information you will need to know for your checkride - they are, by definition, THE source material for all written and practical exams. They're also surprisingly well-written for government publications, and they're free! Definitely a win-win.

To the OP, here are a couple links to get you started:

http://www.faa.gov/regulations_polic...lane_handbook/

http://www.faa.gov/regulations_polic...ilot_handbook/

http://www.ecfr.gov/cgi-bin/ECFR?page=browse (electronic version of the FARs, the book version is much easier to use, but these will ALWAYS be the most current)

The free FAA publications are fine (airplane flying handbook) but I often reccomend Jeppesen products to my students. For new primary students I usually suggest they purchase the Jepp kit which includes textbooks, written test prep, pre solo exam, FAR/AIM, flight computer, plotter, PTS, and a logbook. It all comes in a nifty flight bag which I turned into a gym bag that lasted several years.