Installing Kali on a Windows 8 Computer
The linked Tutorial shows you Step-by-Step How to Install Kali 2016.x GNU/Linux Alongside Microsoft Windows 8 OS.
Kali Linux is an Open Source Project that is Maintained and Funded by Offensive Security, a Provider of World-Class information Security Training and Penetration Testing services.
In addition to Kali Linux, Offensive Security also maintains the Exploit Database and the Free Ethical Hacking Course, Metasploit Unleashed.
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Kali Installation on Top of Windows 8
Installing Kali Alongside Windows 8