I've just reached the opening in chapter 2 wherein there's a brief discussion of concepts and math which should be familiar to the reader (Basic SR stuff it seems), and I'm not familiar with it unfortunately. I am familiar with future and past light cones, and the language of causality, but not the mathematics of, "Lorentz contraction, time dilation, absence of a universal concept of simultaneity... " nor am I more than glancingly familiar with, "4-Vectors in general, and the energy-momentum 4-vector, elementary Lorentz transformations, the Lorentz law for the force on a charged particle, at least one look at one equation in one book that refers to the electromagnetic field tensor..." Obviously I have quite a lot to learn, including much of the basic math. To be clear, this is something I'm doing for personal enrichment, I don't need or expect to come out of this with the kind of skills someone studying this formally would. I'm just using 'Gravitation' as a broad guideline which helps me understand the many gaps in my knowledge I need to fill. What I'm lacking is knowledge of resources (like 'Gravitation') which can help me fill those gaps. I have access to online and offline courses (but I don't know which apply here), and I'd be more than happy to take the time to work through a textbook intended for either, but I don't know which would be helpful. Any assistance in terms of a reading and/or course list would be extremely helpful.