Abstract Johann H.L. Flögel (1834–1918) was an amateur scientist and self-taught microscopist in Germany who 130 years ago pioneered comparative arthropod neuroanatomy. He was fascinated by innovations in optical instrumentation, and his meticulous studies of the insect supraoesophageal ganglia were the first to use serial sections and photomicrographs to characterize the architecture of circumscribed regions of brain tissue. Flögel recognized the interpretative power resulting from observations across various species, and his comparative study of 1878, in particular, provided a baseline for subsequent workers to evolve a secure nomenclature of insect brain structures. His contributions stand out from contemporary accounts by virtue of their disciplined descriptions and emphasis on identifying comparable elements in different taxa. Here we give a biographical sketch of his life and summarize his remarkable achievements.