The thesis comprises three parts, A, B and C. Each part is divided into a number of principle sections which are prefixed by Roman numerals. Most sections are divided into subsections prefixed by Roman numerals. Part A commences with a brief survey of aromaticity and aromatic reactivity in non-benzenoid aromatic compounds. This is followed by a detailed review of the chemistry of perinaphthene and its derivatives. Part B is a discussion of the results achieved in the course of investigations on the perinaphthane nucleus. Part C is the complement to part B, being a description of experimental details.