Proteolysis-targeting chimeras (PROTACs) are an emerging class of bifunctional small molecules that induce targeted protein degradation by hijacking the cell’s ubiquitin–proteasome system. A PROTAC simultaneously binds a protein of interest (POI) and an E3 ubiquitin ligase, forming a ternary complex that leads to ubiquitination and proteasomal destruction of the target protein. Here, we present a concise review of PROTAC technology aimed at synthesizing recent advances in mechanism, molecular components, and rational design. Relevant literature was identified through searches of PubMed, Scopus, and Web of Sci ence up to August 2025. Articles were thematically analyzed to highlight mechanistic principles, structure–activity relationships, and delivery innovations. Evidence consistently shows that efficient degradation depends more on productive ternary-complex formation and cooperativity than on binary binding affinities, that linker geometry and E3 ligase choice are decisive factors for selectivity, and that new approaches such as photoswitchable PROTACs, pro-drug designs, and antibody or aptamer conjugates offer spatiotemporal control. The review concludes that standardization of cooperativity metrics, expansion to new E3 ligases, and integration with clinically validated targeting vectors are key priorities for future development.