Look on the cover/inside the few front pages of the book. If you can't find it stated on/in the book (not all books will say), try a search for the book online (check the publisher's website?) and hopefully you'll find what you're looking for.
If you're looking for books at a certain level, a simple Google search should find what you're looking for.
Addition: Lots of schools use the Accelerated Reader program which gives reading levels to most books so that kids can test appropriately.
You can find book reading levels on websites like Lexile.com, Scholastic.com, or Booksource.com, which provide tools to search for books by reading level. Some libraries and schools also categorize books by reading level or use tools like Accelerated Reader to determine appropriate reading levels for students.
Try reading the book and the answers will be there.
I need to know where I can find the reading textbook.
Try reading it and find out. (:
Look in the book/reading sections?
bookwizard.scholastic.com has a search to find grade levels for books.
The Twilight Saga isn't a ver high reading level, but it is a book for mature readers. The Host is also a good book by Stephenie Meyer. There is also Prom Nights From Hell.
http://www.scholastic.com/bookwizard/ will let you find books that fit their reading level, and as they progress in reading levels, you can order more advanced books.
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Read the book and take notes.
When looking for a book reading device there are many to chose from. Do your research to find the one that is best for you at eBook-reader-review.toptenreviews.com
By reading the book.
Close reading · Slow reading.Speed reading · Subvocalization.