This book isn't a text book, and doesn't want to be, but for Fourier Analysis, "Who is Fourier? A Mathematical Adventure" provides an introduction to the subjec

This book isn't a text book, and doesn't want to be, but for Fourier Analysis, "Who is Fourier? A Mathematical Adventure" provides an introduction to the subject that, IMO, few books can match: https://www.amazon.com/Who-Fourier-Mathematical-Adventure-2nd/dp/0964350432 https://www.amazon.com/Who-Fourier-Mathematical-Adventure-2n...