This book examines topical data on the subject of chemical reactions in different phases of gas, liquid and solid states, such as the classification of polymers in reactivity toward nitrogen oxide; influence of the initiation rate of radicals on the kinetic characteristics of quercetin and dihydroquercetin in the methyl oleate oxidation; supercritical carbon dioxide swelling of polyheteroarylenes synthesised in N-methylpyrrolidone; inhibition of 2-hexenal oxidation by essential oils of ginger, marjoram, juniper berry, black and white pepper; specific properties of some biological composite materials; properties and applications of aminoxyl radicals in polymer chemistry and others.