Description Book 4 in the Libritos Mariposa series includes open syllables with j, c, and g. Each decodable book focuses on one of the most basic units of a word: the syllable. The books begin with simple syllables and progress to more complex ones. Each text is accompanied by full-color illustrations to support beginning readers. The series and format were created by Guadalupe V. Lopez, a bilingual author and educator. The Open Syllables category includes eight titles.