Service discovery is a crucial component of microservice architectures, enabling applications and services to locate each other on a network. The concept has evolved over time, from manual text files to DNS, and now encompasses various approaches such as using existing DNS infrastructure, strongly consistent key-value datastores like Apache Zookeeper or Consul, and specialized service discovery solutions like Netflix Eureka. Each approach has its advantages and limitations, including the need for clients that can register and resolve services, handle heartbeats and failover, and implement caching and load balancing algorithms. The choice of service discovery strategy depends on factors such as language support, scalability requirements, and operational overhead. Ultimately, a well-designed service discovery solution is essential for building a resilient and scalable microservices architecture.