First of all there are two totally different novels with the title Invisible Man. One is a science fiction novel by H.G. Wells, in this one- rather like Jekyll and Hyde the Invisible man lets his...
The protagonist in this amazing novel actually goes without a name for the entirety of the story. Although he refers to himself as Jack the Bear, the reference is in jest.
Invisible Man, like much literature written in the last 125 years, is subject to copyright law. If you do find it online and you don't purchase it, it is a crime and you will be punished.