For someone who has been on the search for the perfect book light for as long as I have been reading (which is quite some time now!), this is perfect.  What clued me in to this product was that one of the previous reviewers spoke of its lightness.  Having used this book light for several months now, I realize that had I purchased something "clunkier" it would not have suited my needs.  This book light is light enough to clip on to a paperback, and of course works perfectly with a hard cover book.  The neck is totally flexible, so you can adjust the light any way you want.  The quality of the light itself is clear and crisp without being overly bright.  The battery power seems to last just as one would hope/expect--I see no need to change the batteries in the near future (I have been using this light for three months now, I think, and I read every night).  Can i say it: POIFECT! :D