Aimed at children aged 4-8, each book introduces only a few letter/sounds at a time allowing independent reading from the outset.
Four books in each unit provide practice whilst offering different stories. Each unit introduces new letters/sounds while revising previously taught phonic letters/sounds and high-frequency or sight words.
The first books have words using the sounds s, a, t, I, and m. Later books use these sounds and gradually introduce new ones. By the end of Unit 7, all the initial sounds of the alphabet will have been introduced.