I am looking for an introductory book on "Hyperbolic Geometry" for self-study.
What is the gentlest note/book on this subject.
Free online book or a PDF would be much better.
I really appreciate that any help you can provide.
(I am familiar with complex variables but not with differential geometry)
I think also Marvin Greenbergs“Euclidean and Non-Euclidean Geometries: Development and History" Is a good way to start but would advise against the expensive 4th edition maybe best to start with a second hand copy of an earlier version.
But I am a bit wondering what do you want to learn about hyperbolic geometry for subfields there are better introductions
Good luck