This new translation of On Coming to Be and Passing Away and Meteorology 1 and 4 fits seamlessly with the other volumes in the New Hackett Aristotle Series, enabling Anglophone readers to study these works in a way previously not possible. The Introduction describes the book that lies ahead, explaining what it is about, what it is trying to do, how it goes about doing it, and what sort of audience it presupposes. Sequentially numbered, cross-referenced endnotes provide the information most needed at each juncture, while a detailed Index indicates the places where focused discussion of key notions occurs.