|Born||August 2, 1847|
|Alma mater||University of Uppsala|
|Known for||Studies of worms; Cultivation of raisins and figs|
|Institutions||California Academy of Sciences|
Gustavus Augustus Eisen was a Swedish-American polymath. He became a member of California Academy of Sciences in 1874 and a Life Member in 1883. In 1893, he became the 'Curator of Archaeology, Ethnology, and Lower Animals' at the Academy. He later changed titles to 'Curator of Marine Invertebrates'. In 1938, he was appointed as an 'Honorary Member', which is considered the highest honor from the Academy.
He was known to have diverse interests, including "art and art history, archeology and anthropology, agronomy and horticulture, history of science, geography and cartography, cytology, and protozoology, as well as marine invertebrate zoology" 
A 2012 article in the San Francisco Chronicle describes him as, "One of those 19th century polymaths, Eisen also studied malaria-vector mosquitoes, founded a vineyard in Fresno, introduced avocados and Smyrna figs to California, campaigned to save the giant sequoias, and wrote a multivolume book about the Holy Grail." 
He is perhaps best known for his studies of oligochete worms and many species were named after him including those in the genus Eisenia. In addition, he is considered to have been responsible for the introduction of the avocado and the smyrna fig to California and he wrote a detailed history of figs 
He was a correspondent of Charles Darwin and his work was referenced by Darwin in The Formation of Vegetable Mould through the Action of Worms 
Mt. Eisen, in the Sierra Nevada in California, was named after him.
Organisms named after him
- Anopheles eiseni Coquillett
- Eisen, G.A. 1888. On the anatomy of Sutroa rostrata, a new annelid of the sub-family Lumbriculina. Memoirs of the California Academy of Sciences 2(1):1–9.
- Eisen, G.A. 1890. The raisin industry. A practical treatise on the raisin grapes, their history, culture and curing. Available online at https://archive.org/details/raisinindustrypr00eise.
- Eisen, G.A. 1893. Anatomical studies on new species of Ocnerodrilus. Proceedings of the California Academy
- of Sciences, ser. 2, 3:228–290.
- Eisen, G.A. 1894. On California Eudrilidae. Memoirs of the California Academy of Sciences 2(3):21–62.
- Eisen, G.A. 1895. Pacific Coast Oligochaeta I. Memoirs of the California Academy of Sciences 2(4):63–122.
- Eisen, G.A. 1896. Pacific Coast Oligochaeta II. Memoirs of the California Academy of Sciences 2(5):123–200.
- Eisen, G.A. 1897. Plasmocytes; the survival of the centrosomes and archoplasm of the nucleated erythrocytes, as free and independent elements in the blood of Batrachoseps attenuatus Esch. Proceedings of the California Academy of Sciences, ser. 3, Zoology, 1(1):1–72.
- Eisen, G.A. 1897. Explorations in the Cape Region of Baja California. Journal of the American Geographical Society of New York, Vol. 29, No. 3 (1897), pp. 271–280.
- Eisen, G.A. 1899. Notes on North-American earthworms of the genus Diplocardia. Zoological Bulletin Vol. 2, No. 4, Feb., 1899 . https://www.jstor.org/stable/10.2307/1535422
- Eisen, G.A. 1900. Researches in American Oligochaeta, with especial reference to those of the Pacific coast and adjacent islands. Proceedings of the California Academy of Sciences, ser. 3, Zoology, 2(2):85–276.
- Eisen, G.A. 1900. Explorations in the Cape Region of Baja California. Journal of the American Geographical Society of New York. https://www.jstor.org/stable/10.2307/197262
- Eisen, G.A. 1900. The Spermatogenesis of Batrachoseps. Polymorphous spermatogonia, auxocytes, and spermatocytes. Journal of Morphology. DOI: 10.1002/jmor.1050170102.
- Eisen, G. A. 1901. The fig: its history, culture, and curing, with a descriptive catalogue of the known varieties of figs. Available online here: https://archive.org/details/figitshistorycul00eise.
- Eisen, G.A. 1903. The earthquake and volcanic eruption in Guatemala in 1902. Bulletin of the American Geographical Society. https://www.jstor.org/stable/10.2307/197952.
- Williams, Gary C. (2007). "History of Invertebrate Zoology at the California Academy of Sciences". Proceedings of the California Academy of Sciences. 58 (12): 197–239.
- Joe Eaton, Ron Sullivan (March 18, 2012). "Native worms outnumbered by worldly brethren". San Francisco Chronicle.CS1 maint: Uses authors parameter (link)
- Eisen, G. A. 1901. The fig: its history, culture, and curing, with a descriptive catalogue of the known varieties of figs.
- Google Book Image of The Formation of Vegetable Mould through the Action of Worms: by Charles Darwin
- Ann-Lisa Måneskjöld-Lower. "Mount Eisen," Sequoia National Park, California: Final resting place of Dr. Gustavus Augustus Eisen
- "THE CALIMYRNA FIG". The Mildura Cultivator (Vic. : 1888 - 1920). Vic.: National Library of Australia. 14 March 1903. p. 4. Retrieved 11 April 2012.
- "HOW THE GRAPES ARE DIPPED IN DENIA". The Mildura Cultivator (Vic. : 1888 - 1920). Vic.: National Library of Australia. 8 December 1894. p. 9 Edition: TWELVE-PAGE EDITION. Retrieved 11 April 2012.
- Radcliffe, Jane; Fidler, Christina V. "Gustav Eisen (1847-1947) Biographical Sketch" (PDF). California Academy of Sciences.
- Shields, Allan (2006). "Gustav Eisen, Wilderness Steward: An Appraisal". Wayward Tendrils Quarterly. 16 (1).
- Shields, Allan (2010). "Gustav Eisen: A Man of Many Achievements". Wayward Tendrils Quarterly. 20 (1, Supplement).