No less a figure than Bertrand Russell remarked that Aristotle's Physics was ‘extremely influential and dominated science until the time of Galileo'. This was despite the fact that this work is as much a collection of ‘lectures on nature' rather than dealing with the science of physics as we understand the term.
Aristotle considers ‘the principles and causes of change, or movement' behind both animate and inanimate things. It is philosophy, not science, but over centuries affected the views of those involved in the ‘natural sciences'.
The text emerged from the Lyceum, the school founded by Aristotle, and is accepted to be a compilation of texts, some of which - but perhaps not all - is by Aristotle. Regardless of authorship, its importance is unquestioned.
It is divided into eight books (and further divided into shorter chapters) and begins with an examination into change - and Aristotle's main ideas of matter and form. The investigative net is thrown wide to encompass infinity, causation, movement, void, time and continuity. The study concludes in book VIII (the longest book) with a consideration of the universe and its nature - eternal or finite - and questions the existence of gods, God (a Prime Mover figure?) and the continued existence of motion.
Translation: R. P. Hardie and R. K Gaye.