Bookcases have been quietly blending in with the woodwork for far too long. Fortunately, after years of providing a muted backdrop for artfully arranged objects and book spines, these hardworking built-in and freestanding furniture pieces are no longer doomed to disappear under a coat of plain white. In fact, controlled blasts of color at the back, and maybe on the sides too, can be an ideal way to make collectibles and other display items come alive. Options range from intense jolts of color to soothing neutrals. The only rule is to keep the rest of the space in mind, whether the goal is to create an accent wall, tie together the furnishings, or provide a bit of needed contrast and energy. Read on for ways to emphasize shelf assets while giving a room a fresh new look.