Part I Background.- Nature of aviation turbulence.- A History of Weather Reporting from Aircraft and Turbulence Forecasting for Commercial Aviation.- Instabilities Conducive to Aviation Turbulence.- Turbulence events interpreted by vortex rolls.- Part II Turbulence Detection Methods and Applications.- Airborne in situ measurements of turbulence.- Doppler radar measurements of turbulence.- Remote Turbulence Detection using Ground-Based Doppler Weather Radar.- Relations between lightning and convective turbulence.- LIDAR-based turbulence intensity for aviation applications.- Part III Nowcasting, forecasting, and verification.- A Summary of Turbulence Forecasting Techniques Used by the National Weather Service.- An Airline Perspective: Current and Future Vision for Turbulence Forecasting and Reporting.- Automated Turbulence Forecasting Strategies.- Aviation turbulence forecast verification.- Aviation turbulence ensemble techniques.- Part IV Observational and modeling studies.- Multi-scale observational and numerical modeling studies of the turbulence environment.- Processes underlying near-cloud turbulence.- Modeling Studies of Turbulence Mechanisms Associated with Mesoscale Convective Systems.- Numerical Modeling and Predictability of Mountain Wave-Induced Turbulence and Rotors.- Gravity waves generated by jets and fronts and their relevance for clear-air turbulence.- Turbulence and waves in the upper troposphere and lower stratosphere.- Similarity of stably geophysical stratified flows.- Part V Future developments.- Airborne remote detection of turbulence with forward-looking LIDAR.- Clear-air turbulence in a changing climate.- Application of Aviation Turbulence Information to Air-Traffic Management (ATM).- Research needs.