Deep Learning, Ian Goodfellow, Yoshua Bengio, and Aaron Courville, 2016 (MIT Press) - A foundational textbook that covers the principles of gradient descent as a core optimization method.
Mathematics for Machine Learning, Marc Peter Deisenroth, A. Aldo Faisal, and Cheng Soon Ong, 2020 (Cambridge University Press) - Connects mathematical concepts, including gradients, directly to their use in machine learning algorithms like gradient descent. Freely available online.