"A Pattern Language"

of

"The Timeless Way of Building" 

both by Christopher Alexander.

http://www.amazon.com/s/?ie=UTF8&keywords=a+pattern+language+alexander&tag=googhydr-20&index=aps&hvadid=21442492257&hvpos=1t1&hvexid=&hvnetw=g&hvrand=3667816219117160861&hvpone=&hvptwo=&hvqmt=b&hvdev=t&ref=pd_sl_3wwgzetkuk_b

Form, Space, and Order by D.K. Ching

That book is a standard for most intro to design classes across the country.

^ ^ To add, I've also found "Analysing Architecture" by Simon Unwin to be a great complimentary book to Ching's F/S/O. It covers many of the same themes but in a different way.

I second Analysing Architecture. It's simplicity makes it one of my favorite books on architecture. Very good for beginners (and great to read again after a few years of experience with a different perspective.
 

I received Form, Space, Order for Christmas when I was about 13.  I loved it.

For An Architecture of Reality by Michael Benedikt.  It's a short, very accessible read that talks about how we respond physically to materials and spaces.  Very lovely and poetic, though the black and white images are not high-quality reproduction. 

I second Donna's recommendation, that was freshman year required reading and have read it at least 10 times since, its a good primer and reset button.

Thanks for all the feedback!

I think the Unwin or Ching look best for her.... I'll see if I can find some copies to look at as opposed to the screen preview... or mabye I just need to have them for my library! ;)

Personally, I really like Thermal Delight in Architecture, by Lisa Heschong.