Columbia subject headings:
Darwin, Charles, 1809-1882.
Natural history--Research--Methodology.
Naturalists--England--Biography.
Harvard subject headings:
Darwin, Charles, 1809-1882
Evolution (Biology)--History
Natural history--Research--Methodology.
Naturalists--England--Biography
Princeton subject headings:
Darwin, Charles, 1809-1882.
Natural history--Research--Methodology.
Naturalists--England--Biography.