Proxy caching effectively reduces the network resources that Web services consume, while minimizing user access latencies. Deploying Web caching proxies over the Internet is not easy, however, and presents several cache management challenges. We offer an overview of key management problems for Web proxy caching and prefetching and present state-of-the-art solutions to these problems. Our focus is on the distribution of conventional Web objects, such as HTML pages and images, but we also address issues arising from emerging applications and services, such as streaming media.