Scholastic Decodable Readers is a 4-level learing program which helps accelerate children's word identification skills and achieve greater mastery in early reading skills. Each level has 20 sequenced books that gradually increase in level of difficulty. Level D features + Long Vowels (multiple spellings) + Variant Vowels + Controlled Vowels + Two-Syllable Words +Irregular Spellings * Introduces advance vowels, controlled vowels and irregular spellings. * Plenty of review practices that provide opportunities for children to practice, extend and refine their knowledge of letter-sound relationships. * Children progress from reading in sentences to reading in paragraphs.