In my understanding of your book title, this book tells about how to develop Rails Plugins, which is more likely resembling components in other language (perhaps like ActiveX in Visual Basic or JSP Custom Taglib in Java EE). Is it true? And does this book suit for Rails beginner like me? Thank you.
The book is *mostly* about leveraging pre-existing third party plugins in your Rails projects, although we also discuss how to develop your own. It's well suited to developers that are new to the framework but does assume that you understand basic Ruby syntax and Rails conventions.
See the other current threads for a description of exactly what plugins are!