This book describes the events and alliances that led up to World War II, including the reasons that various nations joined the fight. In addition to historic photos, this book includes a table of contents, two infographics, critical thinking questions, two A Closer Look special features, a reading comprehension quiz, a glossary, additional resources, and an index. This Focus Readers title is at the Voyager level, aligned to reading levels of grades 5-6 and interest levels of grades 5-9.