Atmospheric boundary layer (ABL) is one of the important area in the the unsolved classical physics. Roll of atmospheric boundary layer have been increasingly investigated since the IIOE period to improve the monsoon predictions. ABL is the layer just above the earth surface and influenced by the surface forcing with a short time span of an hour or less. ABL plays significant role in exchange of momentum, heat and moisture from the surface to the free atmosphere. In this book, we tried to present many relevant studies done by various scientists. Also we included the dynamic and thermodynamic characteristics of ABL over marine, coastal and inland areas on different temporal domains. The ABL studies are important in the tropical region especially over the Indian region where monsoon plays a vital role. Thus major scientific problems addressed in this book are coastal meteorological phenomena, characteristics in the ABL during active and weak monsoon phases, spatial and seasonal variations of ABL over marine atmosphere and the variation of the boundary layer structure over an inland station.