Abbe, Cleveland (1838–1916)
Abler, Ronald (Francis) (1939– )
Adams, Leason Heberling (1887–1969)
Agassiz, Alexander (Emmanuel Rodolphe) (1835–1910)
Agassiz, (Jean) Louis Rodolphe (1807–1873)
Agricola, Georgius (1490–1555)
Allen, Clarence Roderic (1925–2021)
Anderson, Don Lynn (1933– )
Anthes, Richard (Allen) (1944– )
Arkell, William Joscelyn (1904–1958)