How do we know about the men and women who broke important World War II military and diplomatic codes? What were the challenges? Using documentary, archaeological, and oral evidence, this book shows how we know about the Allied codebreakers and their experiences from primary and other sources. Follow along with historians to piece together the fascinating story of those who provided the top-secret information known as Ultra and Magic.Includes: Images of primary source documents Timeline Glossary Resources for more investigationLexile Measure: 1130LCopyright 2014. Middle school. 7 x 9 inches. Softcover, 64 pages.