World War II was the biggest and deadliest war in history. From 1939 to 1945, more than 50 nations fought across the globe as some nations invaded others to expand their own borders. World War II explains the causes, leaders, and major battles of this conflict, while also exploring its outcomes and legacy today. Core Library is the must-have line of nonfiction books for supporting the Common Core State Standards for grades 4-8. Core Library Features: A wide variety of high-interest topics, Well-researched, clearly written informational text, Primary sources with accompanying questions, Multiple prompts and activities for writing, reading, and critical thinking, Charts, graphs, diagrams, timelines, and maps.