Organizing books in a personal library can be a challenge, especially if you are visually impaired. Finding a science fiction book by removing each book to read the larger print on the cover is not practical. Design Observer recently blogged about a slightly unconventional way of Organizing Our Books by Color instead of by author, title, or subject. According to the article, arranging books by color is not only "cool to look at", but some even argue that it helps "discover new and unexpected relationships between books" - suggesting that certain color books are associated with certain subjects or moods.
I can see this working organizationally for a visually impaired person's small library, because for books we are very familiar with, we often recognize them by the color of the cover. Sorting your books by color gives you a reference point for where to look on the shelf.