I have to say, I'm with Anita on this one.
Sure, you can remove all the adult content and put his books and baskets of his toys on the bottom shelf, but unless you *need* to use those shelves to store his toys, I think you're passing up a golden opportunity for learning here. The best way to 'babyproof' a book case is to teach the baby not to touch the contents.
I have shelves full of knick-knacks, photos and DVDs right down to the floor in my living room and I taught DD #1 (now 4 1/2) and we're working with DD #2 (now 11 months) that the stuff on those shelves is off limits. (I learned this was possible by seeing my older sister's kids learn it - they are now 10, 8 & 6) Remember, a baby as young as 6 months can learn to do or *not do* certain things, and that babies/toddlers can understand us much earlier than they can communicate *back* to us through talking.
I never used the term 'No' with my babies (until DD #1 was at least 18 months and talking - she learned it from daycare.) I say "Not for Lydia" for the things my baby can't touch and I immediately redirect to a suitable toy with emphasis "*This* is for Lydia."
Yes, you will repeat it a LOT at first, but my daughters learned some boundaries early on and the phrase worked well for many occasions - baby on your lap, reaching for your drink/knife/fork/etc? -over at a friend or relative's house not 'dumbed down' for babies? -at a restaurant/ church/ hotel/ public building? It has saved my Christmas tree ornaments, the dog's water and food bowls, my photo frames & books and I'm sure countless other stuff over the years.
If you choose to make all the space full of his toys now, at what point do you start to make some boundaries for him? You will also never be able to relax at someone else's house unless they have similarly 'dumbed down' their shelves - you will need to constantly be alert to keep him from trashing their stuff.
Also, I am a huge reader and my house is *full* of books, there are shelves/baskets in each room of the house (except the bathrooms & dining room. =) The baby's room also has a wicker basket on the floor for her board books, so she can get them easily. I demonstrated being 'gentle' with books just like I demonstrated how to be 'gentle' with the dog. My books were 'not for [baby name]' and I redirected to her own books with '*this* is for [baby name]' (The repetition of her name really seemed to help with recognition that I was talking to her.)
As my DD #1 got older, we let her 'read' the magazines we were done with and the glossy circulars and 'magazine' in the paper every weekend. She loved looking at the pictures and pretending to read 'like big people', and she also learned how to handle the pages so as not to rip them.
HTH and Good Luck!