The historical development of membrane research can be divided into three periods: "Early Membraneology" (approximately 1850-1940), "Classical Membraneology" (1940-1970), and "Modern Membraneology" (1970 to date). The "Early Period" is characterized by imaginative conceptual leaps based on technically simple experiments. Each of the latter periods is characterized by substantial increases in activity as measured by numbers of membrane-oriented investigators and of published papers. The transition into each new period is based on technical rather than conceptual breakthroughs. It is concluded that, in membrane research, technical advances tend to precede conceptual advances and that new technologies allow new directions in experimentation, leading to new levels of understanding.