<p><i>Organic Reaction Mechanisms 2019</i>, the 55th annual volume in this highly successful and unique series, surveys research on organic reaction mechanisms described in the available literature dated 2019.</p> <p>The following classes of organic reaction mechanisms are comprehensively reviewed:</p> <ul> <li>Reaction of Aldehydes and Ketones and their Derivatives</li> <li>Reactions of Carboxylic, Phosphoric, and Sulfonic Acids and their Derivatives</li> <li>Oxidation and Reduction</li> <li>Carbenes and Nitrenes</li> <li>Nucleophilic Aromatic Substitution</li> <li>Electrophilic Aromatic Substitution</li> <li>Carbocations</li> <li>Nucleophilic Aliphatic Substitution</li> <li>Carbanions and Electrophilic Aliphatic Substitution</li> <li>Elimination Reactions</li> <li>Polar Addition Reactions</li> <li>Cycloaddition Reactions</li> <li>Molecular Rearrangements</li> <li>Radicals</li> </ul> <p>An experienced team of authors compile these reviews every year, so that the reader can rely on a continuing quality of selection and presentation.</p>