Aldol Reactions with Preformed Enolates.- Magnesium Enolates.- Boron Enolates.- Titanium Enolates.- Tin Enolates.- Catalytic Aldol Additions.- Lewis Acid-Catalysed Aldol Reactions.- Tin Lewis Acids.- Boron Lewis Acids.- Copper Lewis Acids.- Silver, Palladium and Platinum Lewis Acids.- Zirconium Lewis Acids.- Miscellaneous Lewis Acids.- Lewis Base-Catalysed Aldol Additions.- Direct Aldol Addition.- Gold- and Rhodium-Catalysed Aldol Additions.- Antibody-Catalysed Aldol Addition.- Enzyme-Catalysed Aldol Addition.- Organocatalysed Aldol Addition.