The present volume contains contributions presented at the NATO Advanced Study Institute on Molecular Ions held on the island of Kos, Greece, from September 30 to October 10, 1980. The meeting was attended by some 60 participants from 15 different countries. It was the first meeting devoted exclusively to the topic of molecular ions. Its vitality derived from bringing together experts and students from a wide variety of disciplines, whose studies bear upon the structure of molecular ions. The aim of the meeting was to assemble these scientists, representing many countries in Europe and North...