This chapter reflects on the emergence and development of English for Specific Purposes (ESP) through both personal experience and major disciplinary shifts. It traces ESP’s movement away from pedagogy-driven general language teaching toward an approach grounded in disciplinary communication practices, genre analysis, and learner needs. Drawing on corpus-based, ethnographic, and genre-oriented research, the chapter highlights how ESP has enhanced understanding of language use in academic and professional contexts. It also illustrates the field’s diversification across domains, genres, and teaching practices, emphasizing ESP’s applied orientation and its ongoing adaptation to digital technologies and evolving communicative demands.