Mighty Bright XtraFlex2 Book Light with Adaptor - Purple
This thing is great.  I have used a variety of book lights over the years and none compare to this light.  It is easy to use and has two \\"light\\" settings.  One is brighter than the other.  The bendy head lets you angle it any way you want.  It is light enough to use on any book.  I use it on all of my paperbacks.  You can use it plugged into the wall or with batteries.  I bought one for my mom and she said it is the best light she has ever use as well.