Basic Ideas -- How Cyclones Work -- Cyclone Flow Pattern and Pressure Drop -- Cyclone Separation Efficiency -- The Muschelknautz Method of Modeling -- Computational Fluid Dynamics -- Dimensional Analysis and Scaling Rules -- Other Factors Influencing Performance -- Measurement Techniques -- Underflow Configurations and Considerations -- Some Special Topics -- Demisting Cyclones -- Foam-Breaking Cyclones -- Design Aspects -- Multicyclone Arrangements.