Rootkits and Invisible Software
Before we begin: the practical use of the course you are going to see has been proven by thousands of people all over the world – beginners and computer geeks as well. People who make their first steps in computer / network security and professionals: network administrators, programmers, pentesters, black- and white hat hackers. Please, read carefully what we'd like to share with you.
A rootkit is a stealthy type of software, typically malicious, designed to hide the existence of certain processes or programs from normal methods of detection and enable continued privileged access to a computer. - definition by Wikipedia
You can ignore the fact that rootkits really exist,
You can pretend that goverment agencies don't use rootkits,
You can even believe that big companies don't spend huge amount of money for developing malicious software that can spy on you and your family,
You can just turn a blind eye on it and ignore these fact.