Inhaltsangabeand General Aspects.- Electrophilic Selenium, Selenocyclizations.- Nucleophilic Selenium.- Radical Reactions Using Selenium Precursors.- Selenium-Stabilized Carbanions.- Selenium at Higher Oxidation State.- Selenocarbonyls.- Selenoxide Elimination and [2,3]Sigmatropic Rearrangement.- Selenium Compounds as Ligands and Catalysts.