Mobile Mobile ad hoc networks (MANET) are infrastructure-free, pervasive and ubiquitous in nature, without any centralized authority. These unique MANET characteristics present several changes to secure them. This book presents a survey of existing detection and response models and techniques for MANETs. Based on the existing limitations, the book also presents Intrusion Detection and Response models and techniques for MANETs. These techniques and models can also be extended for sensor networks. These techniques and models provide a security framework that will detect various attacks and take appropriate measures to control the attack automatically. These models and techniques are based on the concepts derived from the area of statistics, data mining, soft computing and control systems. This book also introduces the concept of Threat Index, a measure used to detect whether a node in MANET is under attack or not. The effectiveness of the models and techniques is mathematically analyzed using probability techniques and through the performance evaluation experiments.