Sometimes when you play your favorite video game, you can find yourself repeating simple actions. Perhaps this process reminds you of working with old manual machines. You would mount a piece of metal, press the button to launch the drill, pull the lever down, and so forth. But wait a minute. We live in the 21st century, and long before us people have learned ways to automate simple, monotonous actions. These thoughts occurred to me while I was playing my favorite video game. After that, I decided to start looking for ways to automate my game process. I have visited plenty of forums and websites. Most of the applications for game automation that I found contained malicious software. Some of them were virus-free, but they did not work at all. During my searches, people with strange nicknames suggested that I buy these black magic applications that should solve all my problems. But it seems pretty weird to buy something from an anonymous person over the Internet without any guarantees. Further, I realized why bot developers prefer to hide their names. Thus, my searches failed. My next step was an attempt to implement a bot myself. But I faced a shortage of systematic documentation about the topic, despite the fact that bot applications often solve difficult algorithmic tasks and are based on several information technology domains. The situation looked very strange, because this kind of software can be very complex, and moreover, bot development has a long history. Enthusiasts and professional software developers found a lot of solutions and approaches to effectively solving this task. Why didn’t anybody care about sharing this kind of information? This book is an attempt to overcome this information vacuum around the topic of bot development. You will find a bot classification here that I developed from my experience and research. We will consider the internal mechanisms of different kinds of bots and will try to write simple prototypes. You will learn about tools for bot development as well as anticheating systems for preventing usage of the bots. The book will be interesting to all players who want to discover a new sense and approach to the game process. It will also be useful for players who do not care about bot application internals but just want to buy one and use it. You will learn about the available kinds of bots and which exploitation issues you may face. I hope everybody will find something interesting and new in this book.