Memory management is a crucial function of a computer's operating system that oversees how memory is allocated and used. It ensures that each program has enough memory to run efficiently while preventing one program from interfering with another's memory space. This helps maintain system stability and performance. Additionally, memory management involves tracking available memory, allocating it to programs when needed, and reclaiming it when programs are finished. Techniques like paging and segmentation are used to optimize memory usage, allowing multiple applications to run simultaneously without crashing or slowing down the system.