The development and application of cryocoolers - small cryogenic refrigerators designed to provide localized cooling at cryogenic temperatures - is expanding at an ever increasing rate. Small, highly portable cryocoolers are serving growing numbers of advanced infrared sensor and viewing systems; others provide cooling for medical applications, laboratory experiments, vacuum cryopumps, and advanced radio-frequency devices. Long-life spacecraft cooling for space infrared and gamma-ray instruments is a growing field, as is serving the expanding high-temperature superconductor community, and the emerging field of cryogenic cooling of computer systems. Composed of papers written by leading engineers and scientists in the field, Cryocoolers 12 reports the most recent advances in cryocooler development, contains extensive performance test results and comparisons, and relates the latest experience in integrating cryocoolers into advanced applications. The contributions contained in Cryocoolers 12 will be a valuable asset for researchers, product designers, and development engineers associated with the design and application of cryocoolers to the ever expanding number of military, space, semiconductor, medical, computing, and high-temperature superconductor cryogenic applications.