There are many "getting started" Selenium manuals in the market today, such as Selenium Testing Tools Cookbook by Packt Publishing. These types of book are great introductions to the Selenium WebDriver technologies, where concepts are broken down into simple steps to allow the user to understand each concept that Selenium, Java, and TestNG bring to the testing world.
Selenium Framework Design in Data-Driven Testing takes those concepts to the next level, assumes that the user has working knowledge of Java, TestNG, and Selenium, and teaches them how to design and build a scalable, efficient, object-oriented, data-driven test framework. In that respect, this manual is geared toward the quality assurance and development professionals responsible for designing and building enterprise-based testing frameworks.