The texts in this series are aimed at teenagers and adults with reading ages below ten, or adult students learning English as a foreign language. They are assessed by the Basic Skills Agency for content, structure and layout, and are designed specifically to sustain students' interest with storylines and illustrations. Written by special needs teachers, the Investigates books offer accounts of careers, hobbies, sports, extreme sports, disasters, mysteries and animals, and are designed for those with reading ages between six and nine years.