An Interrupt Request (IRQ) is a signal sent to the processor by hardware or software indicating that an event needs immediate attention. This allows the CPU to pause its current tasks and address the request, ensuring that important operations, like responding to user inputs or managing data transfers, are handled promptly. IRQs are essential for efficient multitasking in computer systems. Each device, such as a keyboard, mouse, or network card, is assigned a unique IRQ number, allowing the CPU to identify which device is requesting service. This system helps maintain smooth operation and responsiveness in computing environments.