What is the difference between the Learn to Read program and the Learn to Read Completes and Levels?

Hooked on Phonics Learn to Read is an 8-level program that takes children from letter names and sounds all the way through long-vowel sounds, complex vowels, consonant blends, and challenging sound combination. By the end of the program, your child should be reading at a second grade reading level. The Learn to Read Completes and Levels are components of this complete program. You do not have to purchase the Completes or Levels if you have the complete program.