This title takes a close look at the operatives who collected intelligence for the Union and the Confederacy during the Civil War, introducing readers to these colorful characters and explaining how they carried out their risky missions. Gripping narrative text, historic photographs, and primary sources make the book perfect for report writing. Features include a glossary, additional resources, source notes, and an index, plus a timeline and essential facts. Aligned to Common Core Standards and correlated to state standards. Essential Library is an imprint of Abdo Publishing, a division of ABDO.