Abstract: Minimal thinness is a notion that describes the smallness of a set $A\subset D$ near a boundary point of $D$. This concept was introduced in the late 1940's in the setting of classical potential theory. In the 1950's, Doob gave a probabilistic characterization in terms of brownina motion. Almost all the subsequent work on minimal thinness were in the setting of classical potential theory or equivalently in the setting of Brownina motion. In this talk, I will give a survey of recent results on minimal thinness for general symmetric Markov process.