Science, medicine, and technology seek knowledge to understand or control the natural world. This chapter draws together science and medicine, occupations primarily of the educated elite, with technology often practiced by slaves or foreigners. Some scholars bridged that gap, particularly those treating architecture, mechanics, poliorcetics, or medicine. A greater number of scientists and engineers, particularly ca. 320-200, accumulated more new knowledge than during any other three centuries of antiquity, and more scientific documents survive from this era than any other kind of writing. But, owing to disproportionately larger losses both of Hellenistic material and of works from all ancient eras on science, medicine, and technology, we consequently rely heavily on fragments quoted or paraphrased by writers in the first centuries of the Roman era.

The kingdoms of Alexander’s successors promoted science and engineering due both to governmental patronage and multicultural context. Warfare, trade, and prestige elicited or even demanded the growth of science and engineering. Greeks like Herodotos and Ktesias had admired the ancient civilizations of Egypt and Mesopotamia, and now elite members of the new Greek kingdoms - rulers, merchants, and scholars - found fresh material to contemplate and adapt in the ideas and practices of the conquered peoples.