After a long time starting my review with the third chapter! This chapter jots down all necessary concepts of Probability and Information theory in regards to the future scope of the book. While probability theory is introduced as a mathematical framework for representing uncertain statements, the information theory is introduced as the quantifying concept for the uncertainty. For deeper understanding, an additional resources would be good to consult like Jaynes(2003). Truly computer science does not require the study of uncertainty until the machines start to learn from data. Because data and learning processes have uncertainty. The authors describe about the source of uncertainty. There are three possible sources of uncertainty: - Inherent stochasticity in the system. - Incomplete Observability. - Incomplete Modeling. There is always scop