Apache Hadoop is an open-source software framework used for distributed storage and processing of large datasets across clusters of computers. Coursera's Apache Hadoop catalogue teaches you about the core concepts and components of this powerful framework. You'll learn about Hadoop's architecture, its key components like Hadoop Distributed File System (HDFS) and MapReduce, as well as advanced topics such as data ingestion with tools like Flume and Sqoop. You will also delve into data processing using Hive and Pig, and explore scalable machine learning algorithms. By mastering Apache Hadoop, you will be equipped to handle big data challenges, contributing to business insights and decision making.