"on the book" "en el Libro"
la mochila is how you say book bag in spanish
Libro de texto(Literally "book of text")
you say it `este libro'.
libro
El Libro= The book Libros= Books
cuaderno
nuestro libro
Un librito.
libro bueno.
libro encuadernado
'"The Book" in Spanish is "el libro". "The book is black" would be "El libro es negro".
You can say "Tengo un libro grande".