John Wyngaard's experience in turbulence research and teaching spans the Air Force Cambridge Research Laboratories, the Wave Propagation Laboratory of the National Oceanographic and Atmospheric Administration (NOAA) in Boulder, the Atmospheric Analysis and Prediction Division of the National Center for Atmospheric Research (NCAR), and the Department of Meteorology at Pennsylvania State University, where he developed a sequence of courses on turbulence. This book is based on those courses. He has published over 100 refereed journal papers covering theoretical, observational, and numerical modeling aspects of engineering and geophysical turbulence.