In this book the authors present and discuss current data on physical organic chemistry with a focus on such topics as: the development of new organic semiconductors for application in organic electronics; interactions of aqueous-organic mixtures with cellulose; nuclear-chemical generation of Si and Ge -- centred cations; the use of non-conventional thermochemical reference systems for expressing the structure dependent energy of organic compounds; and the electrolytic dissociation of benzenetricarboxylic acids.