Research has taken a big leap since 1969 in security and is evolving tremendously in every aspect. Here by every aspect it means security being enhanced by applying various theories from networks, intrusion detection systems, artificial intelligence, mining etc. To strengthen the security more for both hosts as well as network one may apply the machine learning techniques and this book works on the same domain to intensify the host/network security. Researchers have given huge emphasis on security with artificial intelligence and have successfully applied the algorithms to increase the intensity of security. The approach discussed here is inspired by human learning style i.e. both supervised as well as unsupervised. By using supervised learning algorithms system/network security performance can be enhanced. The book will focus on developing a detection and prevention system and to escalate the efficiency of the system it will incorporate the benefits of machine learning algorithms.