My chemistry text says Aristotle's view that matter was continuous put off exploration of atomic theory until the 17th century. Were there any explorations prior to this?

I'm not sure if this is precisely what you are asking, but there were certainly "atomists" in ancient Greece. The outstanding example is Democritus, who held that change was possible via the action of multiple individual unchanging things (atoms) that make up the large and complex things we see and interact with.

Of course, it is probably a bit anachronistic to refer to the speculative philosophy of Democritus and his fellow atomists as scientific exploration of the atomic theory, which given that you are reading a Chemistry book, is what I assume you are asking about. However, the theory that all matter was made up of small indivisible atoms certainly existed.

A bit off topic, but I would say the real revolution in the 17th century was due more to rejecting Aristotle's picture of causality (in particular of teleological explanations from something's purpose), in favor of a more purely mechanistic one (corresponding roughly to Aristotle's concept of efficient causality).