The causal model depicted graphically in Chapter 1 is purported to be valid for many middle-grade readers, that is, those students who are between ages 8.4 and 13.3 years. When these ages are converted into GE units, then middlegrade readers are in grades 3 through 7, that is, 3.0 to 7.9. Almost all of the students in the middle grades (a) have learned the alphabetic principle, (b) have learned a great deal of cipher knowledge and know how to use phonological decoding skills, and (c) have a great deal of lexical knowledge. Most of these readers are intermediate readers. That is, they have verbal knowledge and pronunciation knowledge at the third-grade level or higher (VL ≥3.0 & PL≥3.0). However, to be an intermediate reader, students cannot read so well that they have become an advanced reader, with VL≥8.0 and PL≥8.0.