The Software Testing Life Cycle (STLC) is a crucial part of the Software Development Life Cycle (SDLC) that ensures high-quality software through structured testing processes like requirement analysis, test planning, and execution. It offers benefits such as improved software quality, reduced costs, early defect detection, and enhanced customer satisfaction while addressing challenges like unclear requirements and limited resources. By adopting STLC, development teams can foster a culture of quality assurance and achieve better project outcomes in a competitive market.