The answer depends on exactly what you are trying to establish.
If you do not know what the object is called:
What do you call this item / object?
If you want to know the title of this book:
What is this book entitled?
What is the title of this book?
If you want to know what the book is about:
What is this book about?
What is the subject of this book?
If you want to know what type of book this is:
What kind /type / genre of book is this?
If you want to know the publisher or author:
Who is the publisher / author of this book?
Who is the book by?
Who published / wrote the book?
You might ask What book is it if you saw someone reading a book:
What book is it (that you are reading)
which is the same as asking:
What are you reading?
To ask What is this book works in a certain context:
What is this book that is causing all the trouble?
What is this book called is unclear as to whether you are asking for the title or the genre or the classification (an atlas, a dictionary for example)