  Let $(X,d)$ be a compact metric space and $f:X \to X$ be a self-map. The
compact dynamical system $(X,f)$ is called sensitive or sensitivity depends on
initial conditions, if there is a positive constant $\delta$ such that in each
non-empty open subset there are distinct points whose iterates will be
$\delta-$apart at same instance. This dynamical property, though being a very
weak one, brings in the essence of unpredictability in the system. In this
article, we survey various sensitivities and some properties implied by and
implying such sensitivities.
