Biff! Bam! Boom!...Score! Inside, meet the running backs who have been some of the NFL's greatest stars! These 48-page books about fascinating subjects like pirates, mummies, and volcanoes are for proficient readers who can understand a rich vocabulary and challenging sentence structure. In addition to the stunning photographs, informative sidebars, and glossary, readers will find archival photographs and paintings. Averaging 4,500 to 5,000 words in length, Level 4 books are 40 percent pictures and 40 percent text. The Dorling Kindersley Readers combine an enticing visual layout with high-interest, easy-to-read stories to captivate and delight young bookworms who are just getting started. Written by leading children's authors and compiled in consultation with literacy experts, these engaging books build reader confidence along with a lifelong appreciation for nonfiction, classic stories, and biographies. There is a DK Reader to interest every child at every level, from preschool to grade 4.