This document provides information about hacking. It defines hacking as the unauthorized access to computer systems or networks, which is illegal. It describes different types of hackers, including white hat hackers who perform security testing, black hat hackers who commit crimes, and grey hat hackers who are in between. The document discusses the history of hacking and some famous hackers. It also outlines different types of hacking like website, network, and password hacking. In addition, it provides reasons why hackers hack and tips for what to do if a system is hacked. Overall, the document gives a broad overview of the definition, types, and aspects of hacking.