Bookcases are offered 
  in the following standard 
  dimensions:
  
  Widths:
   18", 24", 30", 32", 36", 42",
   48", 54", 60" 
  
  Heights:
   24", 30", 36", 42", 48", 54", 
   60", 66", 72", 78", 84", 90",
   96"
  
  Depths:
   10", 12", 16", 20", 24"
     
  Note:
   Bookcases wider than 42"
   are designed with 1 or 2
   uprights.