A rocketborne cryogenic sampler, capable of collecting large, unmodified and uncontaminated high altitude air samples, has been successfully developed, tested and flown. The sampler employs a simple normal shock diffuser inlet and collects a column of air at supersonic speeds during rocket ascent. The sampled air condenses on stainless steel coils cooled with pressurized liquid hydrogen. Some of the experimental applications of this versatile sampling system are discussed. The sampling system, its operation, and its experimental evaluation are described. Preliminary results of the first rocket sampler flight at White Sands Missile Range on 4 September 1968 testify to the fully successful performance of the sampling system.