Genealogy is gray, meticulous, and patiently documentary. It operates on a field of entangled and confused parchments, on documents that have been scratched over and recopied many times....
Genealogy, consequently, requires patience and a knowledge of details, and it depends on a vast accumulation of source material. Its "cyclopean monuments" are constructed from "discreet and apparently insignificant truths and according to a rigorous method"; they cannot be the product of "large and well-meaning errors." In short, genealogy demands relentless erudition. Genealogy does not oppose itself to history as the lofty and profound gaze of the philosopher might compare to the molelike perspective of the scholar; on the contrary, it rejects the metahistorical deployment of ideal significations and indefinite teleologies. It opposes itself to the search for "origins."
Foucault, M. (1994). 'Nietzsche, Genealogy, History' in J. Faubian (ed.), Aesthetics, Method and Epistemology: Essential Works of Foucault 1954-1984 Vol. 2 London: Penguin Books pp. 369-392.