This document discusses stimuli-responsive polymers, which are polymers that change their properties in response to external stimuli like pH, light, temperature, and others. It classifies polymers based on the number of stimuli they respond to, such as single, double, or multi-stimuli responsive. Examples of applications mentioned include controlled drug delivery, artificial muscles, biosensing, and more. The future perspective section discusses developing polymers that can respond intelligently to multiple external stimuli in a predictable way and creating more biomimetic systems with long-term stability.