Introduction

Galaxies are astronomical objects composed of stars, gas, interstellar medium (ISM) and dark matter. Galaxies form and evolve within a complicated aggregation of processes, some caused internally (in-situ) and others externally (ex-situ). A fundamental ex-situ process is galaxy interaction and merging. Galaxy interactions and mergers are an important process to understand when discussing galaxy evolution, as they are not only considered to be one of the fundamental pathways of structure growth in the context of galaxies, but also have been found to be a catalyst for numerous processes related to galaxy evolution. Despite the importance of the process, the relative role of galaxy mergers on galaxy evolution is heavily contested, and quantitative conclusions are yet to be made. This can be traced back to the difficulty in creating a sample of merging galaxies, which can be further traced back to the lack of a method that can create a complete, pure, sample. Previous studies have adopted numerous different methods, all with their advantages and weaknesses. We discuss what galaxy interactions and mergers are, and the various galaxy evolutionary processes believed to be associated with merger activity, and the various conclusions. We also highlight the difficulty of conducting galaxy merger studies, and the methods taken to create galaxy merger samples, before outlining the remainder of this thesis.