• Built-in bookcases are a permanent addition to your house that adds more space for storage and the display of your favorite possessions. The shelves are mounted inside the walls of your home rather than placed along the walls like standalone bookshelves. Add the shelves to the living room, bedroom or kitchen. Some shelves even create an open space between two different rooms, serving as a makeshift bar. When you add shelves of this type to your home, look for trim styles that work with the architectural style of the room.
  
  

Plain Trim Styles

• Plain trim styles are essentially trim that lacks any decoration or ornamentation. You typically find trim of this type on mass-produced pieces of furniture because it's relatively easy to manufacture. The flat trim pieces are applied directly onto the edges of the shelves, giving it a simple and elegant appearance. This trim is sometimes given a slanted edge, which gives it a slightly decorative look. The edges of each piece are cut at an angle, which lets the pieces easily fit together on the corners of the shelf.
  
  

Neo-Classical Trims

• Neo-classical bookcase trims are fancier and more highly decorated than the simple trims. The trim found on these shelves sometimes resembles a fireplace mantel because it consists of multiple parts. The trim on the sides of the shelves is different from the piece placed at the top of the shelf. The smaller side trims are fluted or have some other type of decoration cut out of the wood. The top piece of trim has slanted edges and a high level of decoration, such as an egg and dart pattern cut into the wood. The high level of decoration found in this type of trim makes it better suited for a room with high ceilings or larger rooms where the decorative feel won't overwhelm the space.
  
  

Keystone Style Trims

• When you add a built-in bookcase to your home, you also have the option of choosing an arched bookshelf. Instead of having a flat top to the bookshelf, the top has a rounded shape, which has a less harsh feel than the traditional square or rectangular-shaped shelves. The keystone is a small, decorative medallion placed at the top of the shelf along the upper piece of trim, which draws the eye upwards, giving the room a larger and taller feel. The decorations found on the keystones are sometimes carried over onto the side trim.