What books are written like a comic book but is not a comic book?

It's possible you could mean Trade Paperbacks. Sometimes they print popular issues or collections of issues in bound book form. Some people mistake these for a different type of book, but they are basically the same. Also, Manga is a well known Japanese version of the comic book in which the story goes from the back of the book to the front, and moves down the page and then over. Also there are stories written in book form about comic book characters. I mean, there are full length stories with no pictures that are about comic book characters. You may also be referring to graphic novels.

Graphic novels are also another example of sequential art wherein the comic book is expressed e.g. The Watchmen / V For Vendetta et.al.