The Mars Science Laboratory is the latest and most advanced NASA roving vehicle to explore the surface of Mars. The Curiosity rover has landed in Gale crater and will explore this region assessing conditions on the surface that might be hospitable to life and paving the way for later even more sophisticated exploration of the surface. This book describes the mission, its exploration and scientific objectives, studies leading to the design of the mission and the instruments that accomplish the objectives of the mission. This book is aimed at all those engaged in Martian studies as well as those interested in the origin of life in other environments. It will be a valuable reference for anyone who uses data from the Mars Science Laboratory. Previously published in Space Science Reviews journal, Vol. 170/1-4, 2012.