All 6 Books are NEW and unused from a pet-free and smoke-free home! Excellent science content readers for elementary students! Each of the 3 topics has a red (3rd-4th reading level) and a purple (4th-5th rdg level) version. This allows for a student to read more or less information based on their ability. See photos above to see the difference. These readers would be an excellent supplement to a student's school work. They would also be excellent texts for elementary homeschool science!