This book is for anyone interested in Apache Hadoop and Spark who would like to learn more about Spark. It is for the user who would like to learn how the usage of Spark can be extended with systems like H2O. It is for the user who is interested in graph processing but would like to learn more about graph storage. If the reader wants to know about Apache Spark in the cloud then he/she can learn about https://databricks.com/, the cloud-based system developed by the people who brought them Spark. If you are a developer with some experience with Spark and want to strengthen your knowledge of how to get around in the world of Spark, then this book is ideal for you. Basic knowledge of Linux, Hadoop, and Spark is required to understand this book; reasonable knowledge of Scala is also expected.