"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
nuestro libro
cuaderno
Un librito.
libro encuadernado
libro bueno.
'"The Book" in Spanish is "el libro". "The book is black" would be "El libro es negro".
You can say "Tengo un libro grande".