Mathematics
I really didn't expect to study topology beyond, say Rudin / Point Set Topology etc., but John Lee recommends this book as a pre-requisite to his other two fantastic yellow books 'Introduction to Smooth Manifolds' and 'Introduction to Riemannian Geometry'. It starts slow and won't blow your mind until you've tucked a whole lot dry definitions about open sets, closed sets, clopen sets, subspace topology, discrete topology etc., but I was surprised to find myself pretty gripped by the very clear exposition and good (for mathematics) writing. By the time you get to Homotopy, Fundamental Groups and Baby Homology, you'll find yourself pretty gripped by the material. As always, it's best to just keep moving if you can't understand a definition. It's always clearer in retrospect when you find out what's motivating it. I'm about 3/4 of the way through it as of 09-28-2024, and it's looking like I may push through to the end. 4 stars.