This book presents an in-depth analysis of the airflow structure immediately above the solid and water interfaces, in the presence and absence of the waves. The unique feature of the book is the investigation of the turbulent flow structure in few millimeters above the wave trough that was not reported before in the literature. The study is made possible using the state of art technique called Particle image velocimetry (PIV). The presented results are beneficial, understanding the physics of the complex airflow structure, mechanism of transferring momentum and heat across air-water interface in systematic way.