The Spiderwick Chronicles are written by author Holly Black (Tithe, Ironside) and illustrated by Tony DiTerlizzi.  Together they created a stupendous series and awesome pictures.  The Chronicles are about Jared Grace and his siblings Simon and Mallory.  Together they discover the Field Guide and are launched into a world so much bigger than they are.  On my website you will find the plots of the books and the creatures that are found within them.  Also, there are short biographies of the siblings and the creatures they encounter.  Enjoy!