Pattern Recognition and Machine Learning, Christopher M. Bishop, 2006 (Springer) - A comprehensive textbook providing a probabilistic perspective on machine learning, covering model complexity, generalization, and methods to prevent overfitting.
Machine Learning Lecture Notes, Andrew Ng, 2011 - Lecture notes from a renowned machine learning course, offering clear explanations of bias, variance, overfitting, and the necessity of evaluating models on unseen data.