This book provides a comprehensive overview of NASA’s ICON space mission. Written before ICON’s launch, the papers contain the most complete description of the ICON flight instruments and preflight operation plans. In addition to the technology and engineering, the volume describes ICON’s scientific mission to investigate how lower atmospheric tropospheric dynamics affect the high altitude ionosphere, and why special emphasis was placed on understanding how neutral winds affect the ionospheric dynamics. This book helps researchers better understand ICON’s workings and why ionospheric behavior is so important to technically advanced societies, as systems based on satellite communications and GPS rely on the propagation of radio waves through the ionosphere. Previously published in Space Science Reviews in the Topical Collection “The Ionospheric Connection Explorer (ICON) mission”