Without taking the time to sit down and write a letter to a distant friend or family member, our communication has become more practical, short-form, and casual. Letters, often written with more intention, can include details that reveal the everyday and sometimes intimate details of the writer's life. These qualities also appealed to authors, who have used the form to tell their stories. Novels written in letter form fall under "epistolary novels," and if you've ever read one you know they can be hard to put down. Here is a selection of books penned in letter form you might want to write home about after you finish them.