The Compressed Air Manual is a resource for everyone who wishes to know more about compressed air. This edition, the sixth, is in many respects extended, updated and improved compared to previous editions, of which the last was issued in 1976. Naturally a great deal has happened during these twenty or more years, nevertheless the fundamentals remain and make up the core of this Manual, which has been desired and requested by many. The Manual addresses the essentials of theoretical and practical issues faced by everyone working with compressed air on a day-to-day basis, from the fundamental theoretical relations to more practical advice and tips. The main addition to this edition is an increased concentration on environmental aspects, air quality issues, energy savings and compressed air economy. Furthermore, we conclude with calculation examples as well as diverse, helpful table information and a complete keyword index. The Manual’s contents have been produced by our leading compressed air technicians and I hope that the different sections act both as a textbook for newcomers and a reference book for more experienced users.