Ron Arad bookworm  

I wouldnt
One thing that frequently pops up in design blogs are things like the bookworm - clever designs for bookshelves that completely ignore the way books themselves are designed. As a bookbinder this makes me sad - because books are wonderful things, and should enjoy a long and eventful life, and not be untimely cut down because some jackass decided to stack them at an angle.
(I use jackass as a hypothetical - certainly not you specifically, Simon)
The past 2000 years of bookbinding have been built on the assumption that books will be stacked side by side on horizontal shelves. Everything about books has evolved around this standard: from the depth of the square, to the number of sewing stations on the spine. All of these things are the 'human factors' of the book, so to speak. Imagine a car where the steering wheel is centered on the dashboard because it looks more symmetrical. It makes no sense because people use cars differently. Putting books on an angled shelf will stress the bindings in ways that the book isn't equipped to handle. It will also eff up the pages and the covers - in short, shortening the life of your books.
Unfortunately people seem to think horizontal shelves are boring instead of beautiful. I, however, think that one of the most beautiful things in the world is a shelf full of beautiful books. I literally lost my breath when I walked into the Great Room at Trinity Library (below)

balance act of wife too my view
of how the house should look.
My wife has cook books and wants to display them in the kitchen.
Now she has chosen a wall on which I wanted to have a simple silver brich outline painted, but for marital bliss have given her the space to fit a book shelf.
The book worm was an option she liked instead of my first suggestion of a simple glass shelf spanning 3/4 the width of space giving the effect of floating books.
any ideas on fixing a glass shelf without seeing ugly supports?
I hear your books protection issue lucifer and have a special space behind my desk for those books which are special to me. they include a treasure of scandinavian design, 1st edition design from denmark and several others which i use "when in doubt" and they are neatly lined although not as neatly and large as the library.

Floating glass shelves
Here are two kinds. One that uses a plain wooden block support and the other that appears to be truly floating but which must be installed during construction, prior to putting up the sheetrock.
http://www.floatingglassshelves.com/index.html