5Explore the dark side of space in Out of this World, a new and exciting series for struggling readers. What is antimatter? If we've never seen antimatter, how do we know it exists? These and other fascinating questions are discussed in the Antimatter title using considerate text that is written at a higher maturity level with a lower reading level to engage struggling readers. A table of contents, glossary with simplified pronunciations, and index all enhance reading comprehension. Sidebars include hands-on experiments, spotlight biographies on women in science, tech connections, and far out facts.