"Spies in the Sky" traces the birth and evolution of the Advanced Reconnaissance System, Weapons System 117L (WS-117L), during the Cold War. This narrative unfolds against the backdrop of the space age and geopolitical tensions. It all began in 1946 with Project RAND's exploration of artificial satellites, eventually leading to WS-117L's mission of satellite-based strategic reconnaissance. As the Cold War escalated, the Atlas Intercontinental Ballistic Missile (ICBM) Program's launch capabilities made WS-117L crucial for surveillance and assessing enemy capabilities. The book explores the web of espionage, rivalry, and innovation surrounding WS-117L, Corona, and Hexagon reconnaissance satellite programs, featuring conflicts between government entities like the CIA, NRO, and DoD. Major General Bernard A. Schriever's leadership at the Western Development Division (WDD) in 1955 marked a pivotal moment for WS-117L. Despite challenges and President Eisenhower's scrutiny through the President's Board of Consultants on Foreign Intelligence Activities (PBCFIA), WS-117L transitioned to "Corona" in 1957. Corona faced numerous hurdles, but it achieved a historic milestone by launching and recovering its first spacecraft in 1960. This book unveils Corona's profound impact on American intelligence, national security, and strategic planning, as well as its declassification in the 1990s for scientific and environmental exploration. "Big Brother" uncovers a hidden chapter in American history, showcasing the ingenuity and determination that pushed boundaries in technology and intelligence. It's a story of triumph, innovation, and the lasting influence of satellite reconnaissance. The CORONA reconnaissance satellites, introduced during the challenges of gathering intelligence behind the Iron Curtain, revolutionized intelligence collection. These increasingly advanced satellites provided critical intelligence on nations like the Soviet Union and China, revealing missile complexes, naval fleets, and antiballistic missile activities. CORONA's contributions extended to military mapping data for organizations like the Army Map Service and the Defense Mapping Agency (DMA). The book explores codewords like "KEYHOLE" and "TALENT," illuminating the covert language of intelligence. With the declassification of CORONA imagery and documents, this book comprehensively examines the program's history, operation, and impact. It highlights CORONA's emergence as America's response to the need for detailed photographic coverage of closed-off nations in the 1960s, celebrating the enduring contributions of those involved. "Big Brother's eyes above the Iron Curtain showcase the program's historical significance, drawing on over 2 million linear shelves of historical documents and imagery. It's a testament to innovation, determination, and the relentless pursuit of knowledge in the name of national security.