GUEST POST BY AUTHOR CLAUDIA MILLS:
What’s the Difference Between Early Readers and Chapter Books? 
A previous post discussed the difference between chapter books and middle grade novels. Here, we go the other direction–that of early readers to chapter books. Graciously sharing her thoughts on the topic is author Claudia Mills. She writes both genres of books, and her work has been honored as ALA Notable Books of the Year. See her full profile following this post.
I treat “early reader” and “easy reader” as interchangeable terms. As I categorize them, these are very short texts for newly independent readers. The texts vary in length, but are seldom much longer than 1,000 words, and a premium is put on readability.
The chief device employed to enhance readability is the breaking of the lines on the page with only a few words (perhaps 4–6 words) on each line, giving the visual appearance of poetry; this way emerging readers only need to try to grasp a few words at a time. Paragraph breaks are marked by a space in the text rather than by indentation. Controlled vocabulary is often employed, as well as repetition of words and phrases. Among my favorite examples here are the Frog and Toad books of Arnold Lobel and the Henry and Mudge books of Cynthia Rylant. My own Gus and Grandpa series falls in this category as well. Easy readers usually have full-color throughout with illustrations on every page.
There is a significant leap from easy/early readers to chapter books. Word count springs from 1,000 or so words to 10,000, 15,000 or more. My own chapter books in the Franklin School Friends series are around 15,000 words each. Now we see black and white illustrations, often one per chapter, or perhaps more frequent spot illustrations, 
but seldom do we find art on every page. The chief way that readability is ensured is by keeping paragraphs short. If I see a text with paragraphs routinely extending more than 6 or 7 lines, I say to myself, “This is a middle-grade novel and not a chapter book.” My favorite examples here are the Clementine books of Sara Pennypacker and the Lulu books of Hilary McKay, as well as my own 7 x 9 = Trouble! and How Oliver Olson Changed the World. But of course, there are longer easy readers and shorter chapter books, so the boundaries can be blurred.
Chapter books are now my favorite kind of book to write. I see them as having much of the range and complexity of middle-grade novels, but with brisker, peppier pacing, and a certain sweetness that middle-grade fiction often lacks. They often deal with smaller problems resolved in a shorter time frame. They are written on a child’s scale with those sparkling details that are true to a third grader’s perception of the world. 
Profile: Claudia Mills is the author of 50 books for young readers, including picture books (Ziggy’s Blue-Ribbon Day), easy
readers (the ten books of the Gus and Grandpa series), chapter books (Kelsey Green, Reading Queen, Fractions = Trouble!), and middle-grade novels (Zero Tolerance, One Square Inch). Her books have been named ALA Notable Books of the Year, Blue Ribbon Books from the Center for Children’s Books, and translated into many languages. Dr. Mills, who 
holds a Ph.D. in philosophy from Princeton University, is also an Associate Professor of Philosophy at the University of Colorado at Boulder, where she specializes in ethics and political philosophy, as well as publishing many articles on ethical and philosophical themes in children’s literature.
Chapter Book Chat 