Traditional defense models place defenders at a disadvantage. In contrast, adversaries have been developing strategies to maintain their effectiveness and escape from detection. Moving Target Defense (MTD) has been proposed as a game-changing capability for protection of critical computing and network infrastructure by enabling defenders to change system behaviors, policies, or configurations automatically such that potential attack surfaces are moved in an unpredictable manner. In this talk, I will talk about how MTD takes a page from how botnets worked to influence defensive policies to protect cloud and mobile systems. The talk will provide insights into how MTD based defense implemented at program-level( instruction set), host-level (IP address, memory), Cloud-level, Network-level and Mobile device. We will also discuss the when, where, how of MTD. Finally, I will provide results from MTD work done in my lab in cloud security.