Message passing is a method used in computer science and programming to enable communication between different processes or objects. In this approach, one process sends a message to another, allowing them to share information or request actions. This is particularly useful in distributed systems, where components may be running on different machines. In the context of object-oriented programming, message passing allows objects to interact by sending and receiving messages. Each object can define its own methods, and when a message is sent, the receiving object executes the corresponding method. This promotes modularity and helps manage complexity in software design.