Four essays are presented in this volume, three of which provide an overview into recent research on a current topic. The first two essays concern hypericin and its perylene quinone analogs and the use of thiophosgene in photochemical and photophysical studies. The third essay, titled 1,2-cycloaddition reaction of carbonyl compounds and pentaatomic heterocyclic compounds, by three chemists at the university of the Basilica in Potenza, Italy, concerns the Paterno-Buchi reaction on Furan derivatives and on pentaatomic heterocycles differing from Furan. The editors note that the fourth essay (of 134 pp.), titled The invention of Dylux instant-access imaging materials and the development of Habi chemistry, is unusual for presenting a biographical viewpoint of the author, Rolf Dessauer. The contributors and editors are chemists at universities and in private research institutions in the US, Canada, Italy, India, and Germany.