A comic book is a magazine or book containing sequential art in the form of a narrative. Comic books are often called comics for short. Although the term implies otherwise, the subject matter in comic books is not necessarily humorous, and in fact its dramatic seriousness varies widely. The term "comics" in this context does not refer to comic strips (such as Peanuts or Dilbert). In the last quarter of the 20th century, greater acceptance of the comics form among the general reading populace coincided with a greater usage of the term graphic novel, often meant to differentiate a book of comics with a spine from its stapled, pamphlet form, but the difference between the terms seems fuzzy at best as comics become more widespread in libraries, mainstream bookstores, and other places.
Some of the earliest comic books were simply collections of comic strips that had originally been printed in newspapers, and it was the commercial success of these collections led to work being created specifically for the comic-book form, which fostered specific conventions such as splash pages. Long-form comic books, generally with hardcover or trade-paper binding came to be known as graphic novels, but as noted above, the term's definition is especially fluid. Like jazz and a handful of other cultural artifacts, comic books are a rare indigenous American art form,   though prototypical examples of the form exist.
American comic books have become closely associated with the superhero sub-genre. In the UK, the term comic book is used to refer to American comic books by their readers and collectors, while the general populace would mainly consider a comic book a hardcover book collecting comics stories. The analogous term in the United Kingdom is a comic, short for comic paper or comic magazine.