The fundamental concepts of morphophonemics (MP) are explained, particularly the types of process involved and the nature of underlying representations, and their place within linguistics more broadly. The history of the topic is presented chronologically from Structuralism to divergent approaches within the framework of Generative Phonology. The question of the psychological reality of the key concepts is raised, and the current lack of an agreed approach to or interpretation of the relevant facts is noted. The lack of interest in the domain of MP, as classically understood, in the light of current theoretical trends (2004) is explained.