This document discusses 5 reasons why Apache Spark is in high demand: 1) Low latency processing by keeping data in memory, 2) Support for streaming data through resilient distributed datasets (RDDs), 3) Integration of machine learning and graph processing libraries, 4) DataFrame API for easier data analysis, and 5) Ability to integrate with Hadoop for large scale data processing. It provides details on Spark's architecture and benchmarks showing its faster performance compared to Hadoop for tasks like sorting large datasets.