Professor LIU YouCheng, a well-known organic chemist and one of the pioneers of free-radical chemistry in China, has made numerous outstanding contributions to the development of free-radical chemistry. His research group has investigated a series of free-radical reactions and elucidated the mechanisms. The areas he has studied cover the decomposition mechanism of diacyl peroxides in benzene, revealing for the first time the carboxyl conversion reaction; electron transfer reaction of vinyl Grignard reagents; and the structure and mechanism of C–C bond initiators. In particular, his group has carried out an extensive study on the electron transfer reaction of aminoxyl radicals with biomolecules such as cysteine, glutathione, ascorbic acid and Vitamin E. Liu’s group has also studied radical ion chemistry, photoinduced electron transfer as well as the electron transfer reaction in cyclodextrins and biomimetic systems. His group has clearly demonstrated the electron transfer and concerted hydride transfer and the existence of the intermediate mechanism of coenzyme NADH models. These pioneering studies not only enrich the fundamental theory of free-radical chemistry, but are also of significance to interdisciplinary science such as free-radical biology as well as having practical value in green chemistry. The picture on the cover page illustrates a carbon-centered radical, an oxygen-centered radical, an aminoxyl radical with an electron transfer pathway, and a coenzyme NADH model to exemplify Professor Liu’s research achievements.