The document discusses stochastic processes for modeling stock prices, including Wiener processes, generalized Wiener processes, and Ito processes. It explains that Ito processes are continuous-time, continuous-variable processes best suited for modeling stock prices, with the stock price following a process where the return and volatility are functions of the stock price and time. The document also summarizes Ito's lemma, which describes the stochastic process followed by functions of variables that themselves follow stochastic processes.