I would make a special spot in the house that is specifically designated for books. A part of a book shelf, or, a new book shelf that is for their books only will make books special to them and they will likely pay better attention to their own books.

I would start by really getting down to what they like. Kids, like adults, will spend time exploring their interests. Have a conversation with them about what they like to do--it can be anything. And be ready for anything. I bet you'll fund a book on the subject. If they like boats, find an age appropriate book on boats. Then present the book in a fun way--like wrapping it in gift paper.

You'll see that the presentation and the subject matter may convince them that not all books are hostile entities. Once they get going on one book, they door is open for more.