Rendezvous with Sensitivity

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.