Jesse Russell in The Hedgehog Review:
In his classic book from 1990, Three Rival Versions of Moral Inquiry, the Marxist-turned-Catholic-Thomist philosopher Alasdair MacIntyre discusses three basic modern and postmodern approaches to philosophical inquiry: encyclopedia, genealogy, and tradition. The genealogical method, pioneered by Friedrich Nietzsche and elaborated by Michel Foucault, presents a historical narrative in which ideas develop and grow over time. According to this thinking, being and truth are conditioned by history (historicized) and thus develop in tandem with the twists and turns of science, technology, economics, language, and culture.
A method initiated by critical theorists writing primarily for other intellectuals and academics, the genealogical approach has found surprising success in an unlikely genre: coffee table books.
More here.