 Historically, phylogenetics emerged out of the larger field of biological systematics, the field of biology that studies the diversity of life and the relationships of living things through time. Today, systematists typically treat “relatedness” solely in terms of recency of common ancestry, but this was not always the case. Pre-Darwinian taxonomists discussed the relationships of various groups and their place in the “natural system”, and while the rise of evolutionary theory allowed that one sense of relatedness was genealogical, it did not eliminate the idea of the broader notion. Debates about the role of phylogeny in classification and taxonomy were widespread (e.g., Huxley [ed.] 1940; Winsor 1995) though they began to take on a new form beginning in the late 1950s as collaborations turned into organized research programs pushing their agendas.