2.1 Introduction2.2 Role of Machine Learning in IDSs2.3 Fundamentals of Machine Learning2.4 Data Preparation for IDSs2.5 Supervised Learning for Intrusion Detection2.6 Unsupervised Learning for Intrusion Detection Systems (IDSs)2.7 Semi-Supervised Learning in Intrusion Detection Systems (IDSs)2.8 Reinforcement Learning for Intrusion Detection System2.9 Feature Engineering, Model Training, and Hyperparameter Tuning in IDSReferences