The renaissance in comprehension instruction launched by Mosaic of Thought has led to changes in hundreds of thousands of classrooms, where teachers now model reading strategies, and students probe meaning more deeply. But no book in the field has satisfactorily answered the question: What does it really mean to comprehend? In To Understand, Ellin Oliver Keene not only explores this important question, but reveals what teachers can do to encourage all students to engage in deep understanding far more consistently than before.