Principles of Typography. Beauty of Type.

I'm very well aware that a lot of my research is subjective. I know that people see beauty in a different way. Different designers like different styles, colours, layouts and everything. No designer is the same.
A typeface though has to be in a right setting to be beautiful surely that is the case.
As people know that Sans-serif fonts are quite difficult to read in a book publication, so if a 400 page book was created using a typeface like Helevetica would that make helevetica in that sense ugly? Or what about Garamond as a help sign? Would Garamond then become an ugly typeface.

I feel that with me narrowing down what was a very open subject might be more benefial and less subjective, as there must be set ground rules when and where to use a typeface.