Control Valve Primer: A User's Guide, Fifth Edition

In this new edition, Dr. Baumann—holder of more than 150 patents and author of more than 200 publications on control valves, fluid mechanics, and acoustics—shares his expertise in designing control loops and selecting final control elements. 

Note from the author:
When one thinks of valves, there is a mental image of plumbing items. However, once you realize that, except for electricity, most energy flows through pipes, it becomes obvious how important it is to control the fluid passing through such pipes. After reading the following, you will realize how sophisticated control valves are—quite a  way from the device under your kitchen sink. 
–Hans Baumann