Hello, I am learning General Relativity through some books like 'Gravity' by Hartle and through some other text books. All those books, do not speak of general relativity from the context of differential geometry. I have a fair amount of knowledge of calculus as well as set theory. My understanding why differential geometry is required in GR: (Please correct me if I am wrong) As it deals with curvature and topology hence it requires differential geometry to study curved surfaces. My question: (1) Is differential geometry absolutely necessary to learn General Relativity? (2) Can GR be learned without differential geometry? (3) How much of the GR is related to differential geometry? (4) Can anybody please guide me, a step by step guide to differential geometry? Thanks.