TERL Boosters offer expansion opportunities for your Teen Emergent Reader Libraries. Unlike the libraries, Booster titles are sold individually. Each Booster level supports a TERL library. Boosters can also stand alone and are excellent hi-lo classroom books. There are six Booster titles supporting each level of TERL. STEM Boosters offer a unique way to delve into science, technology, engineering, and math for emergent readers. Verse Boosters introduce readers to the versatility of contemporary poetry.