One of the more recent titles in the “Addison-Wesley Professional Ruby” series, this 12-chapter book covers both simple topics, such as how to use Git as a version control tool for source code, as well as advanced ones, such as how to deal with sessions and how to authenticate users.

The first three chapters are introductory. Chapter 1, “From Zero to Deploy,” includes advice about which tools to use (Git as a version control tool, for example), how to install the required software (such as Ruby or Git), and how to create a simple static application that is later deployed to the Heroku deployment service.

Chapter 2 is concerned with building a very simple Twitter-style application. It discusses the model-view-controller (MVC) pattern, and how to model users and posts using MVC. It also briefly introduces readers to representational state transfer (REST).

In chapter 3, the author starts to build the application that is used throughout the book as an example. Even though Rails is designed for making dynamic Web sites, the application described in chapter 3 consists of mostly static pages. Despite looking rather simple, starting with static content allows the reader to better grasp the implications of each choice. Besides, the chapter covers important topics such as automatic testing and code refactoring. The chapter ends by adding some dynamic content to the page title and by introducing layouts to remove code duplication.

Chapter 4 is completely different from the first three: it explores some parts of the Ruby programming language that are important for Rails, including objects and classes, method definitions, and data structures such as arrays and hash tables.

The first part of chapter 5 deals with cascading style sheets (CSS), the graphical interface of the application, and integration tests, a core part of the test-driven development approach. The second part introduces the topics that the subsequent chapters will cover, including user registration and Web site sign up.

Chapters 6 and 7 discuss the process of creating a model for users. This process includes dealing with issues such as storing data, validating data, securing passwords and authenticating users, and testing.

Chapter 8 is dedicated to the sign-up process (how to add new users and how to test possible scenarios such as missing fields). After adding that feature, the next step is to allow registered users to log in/out of the Web site. Session management is the topic of chapter 9, and chapter 10 discusses updating/deleting users, protecting specific pages, and page forwarding.

Chapter 11 explains how users can add/edit/view posts (again, the example is a simple Twitter-style application). Finally, chapter 12 completes the application by showing readers how to add a social layer that allows users to follow other users.

Overall, the author does a good job, covering important concepts in great detail. It is perhaps worth emphasizing that, since this book is aimed at practitioners, it discusses the step-by-step building of an application from scratch.