I keep my favorite and most referenced books in our den bookcases flanking the fireplace. I have tried many different combinations for organizing the books, but always hesitated to group by color. I have seen color grouping that I loved (Kevin Starkey's office bookshelf) and others that I did not like so much. I decided to give by hue it a try and actually really like the result. It is great when little 15 minute tasks create such a difference.