Apache Spark is a unified analytics engine for large-scale data processing, used for big data and machine learning tasks. Coursera's Apache Spark skill catalogue teaches you about this powerful tool for handling big data analytics. You'll learn the fundamentals of Spark's distributed computing model, its powerful data processing capabilities, and how to implement machine learning algorithms with Spark. You'll also delve into Spark SQL for structured data processing, Spark Streaming for real-time data processing, and MLlib for machine learning tasks. Master these aspects to enhance your data science skills and solve complex computational problems in various industries.