What Is a Just Right Book?
There are three types of books readers will encounter in their reading life: Easy, Just Right and Challenging. In Reading, this is known as the Goldilocks Rule. We want students reading Just Right Books. More importantly -- we want them to know how to pick out books that are Just Right for them.
Easy Books 
You can read every word
It is often a favorite read
You can finish the text quickly
Your reading is smooth with expression
You are not adding to your thinking
It is a light read
Easy Books are good for enjoyment, automatic word identification, fluency and reading practice.
Just Right Books 
You can read most of the words
Your reading is mostly fluent (steady rate, with expression, smooth)
You are able to "get into" the book
You use word and/or thinking strategies to help you
You are interested in the text
You understand what is going on
You are able to talk about what you read
You feel comfortable reading -- it is a good fit
Just Right Books are good for strengthening your reading muscles, building stamina, adding new learning, practicing strategies, acquiring vocabulary and expanding your thinking.
¤ Just Right Books Grow Readers ¤
Challenging Books 
You do not know how to read many of the words
You can read the words but you do not know what they mean
You get confused
You lose track of where you are
Your reading is often choppy and may lack express