RQ is a Python library that uses Redis for queueing jobs and processing them in the background with workers, offering a lower barrier to entry and simplicity compared to other libraries like Celery. It's suitable for executing lengthy or blocking functions, such as networking requests. By setting up an environment with Python 3, pip, and Redis, developers can use RQ to execute asynchronous tasks without blocking the main code. The library provides a simple way to enqueue functions and arguments, making it easy to process tasks like hitting the Mars Rover API. RQ workers run in the background, performing tasks added to the queue, allowing for non-blocking execution of functions that would otherwise block the main code. With RQ, developers can add asynchronous task processing to their projects with minimal additional code.